I think this post makes a very important and useful claim, but one that is obscured by the use of the word 'fascism', which -- as the post itself admits -- has for decades had a very charged meaning and has been used in inconsistent ways. It seems as though it is usually used to draw an analogy with the WW2-era Axis powers, but the movements that you're highlighting lack some very important characteristics that those regimes had. Most importantly, under Modi/Orbán/Erdogan, control by the ruling party has never been total; opposition parties control the capital cities in all three countries, and are generally permitted to participate in elections which may not be fair because of media policies but are fairly free. (Also, the movements you highlight are usually not militaristic: Erdogan has had a famously strained relationship with the Turkish military, and most 'populists' in other nations have won running against the entire old elite, which includes the military leadership. They are also rarely or never expansionist.)
But it is very clear that there is a global trend away from rule by a set of 'cosmopolitan' elites (...the details of these elites actually differing a great deal between different countries) towards parties which deliberately try to contrast themselves with those elites. This has usually only resulted in actual dictatorships in Latin American left-populist countries (cf. Maduro in Venezuela, Ortega in Nicaragua), but the most common presentation globally is as right-populism which strengthens enough to begin changing the country's constitutional framework (true for all of Modi/Orbán/Erdogan) in ways that tend to strengthen its own hold on power.
Part of the danger here might be that many voters are inclined to vote for people or groups who have histories of being 'really' opposed to the establishment, which might select for extremists because anyone who wants to change the system but is not an extremist will probably choose to work within it. (This explains the military hostility, since it is usually the loudest defenders of the status quo who seek military careers; this may be far-right in certain contexts, but it is conspicuously not the kind of far-right which is gaining power, which is moderately to greatly hostile to status quo politics and therefore predictably has conflicts with the military. 1920s and 1930s-era fascists, who wanted to conquer neighboring countries, were able to get around this by explicitly giving the military more power and making it higher-status, but this would be very counterproductive for today's far-right governments.) Thus, today's paradigmatic parties are ones like the National Front in France (which originated as a Vichy-nostalgist organization) and the Sweden Democrats in Sweden (...originally very literal neo-Nazis), both of which moderated in response to getting closer to power. It's very noticeable that taboos on cooperation with both of these parties broke in 2022, and the same year Brothers of Italy (for whom the taboo broke long ago) became the dominant party in the Italian government.
The cause of the trend appearing at once in many different countries is tough to pinpoint; it may be that some degree of authoritarianism has always been popular and modern communications networks have made it easier for ordinary people to organize. (I think David Shor has written that in the modern social-media environment the civil rights movement may have failed, for instance). The sum of all authoritarian tendencies in developed democratic countries may be constant (it feels kind of tough to say that 2010s/2020s Republicans are really more authoritarian than the government which did MKUltra/Tuskegee/suppressing dissent with the fairness doctrine), and it may be that it is now harder to get away with that sort of thing unless your supporters really do not care, in their heart of hearts.
I think this post makes a very important and useful claim, but one that is obscured by the use of the word 'fascism', which -- as the post itself admits -- has for decades had a very charged meaning and has been used in inconsistent ways. It seems as though it is usually used to draw an analogy with the WW2-era Axis powers, but the movements that you're highlighting lack some very important characteristics that those regimes had. Most importantly, under Modi/Orbán/Erdogan, control by the ruling party has never been total; opposition parties control the capital cities in all three countries, and are generally permitted to participate in elections which may not be fair because of media policies but are fairly free. (Also, the movements you highlight are usually not militaristic: Erdogan has had a famously strained relationship with the Turkish military, and most 'populists' in other nations have won running against the entire old elite, which includes the military leadership. They are also rarely or never expansionist.)
But it is very clear that there is a global trend away from rule by a set of 'cosmopolitan' elites (...the details of these elites actually differing a great deal between different countries) towards parties which deliberately try to contrast themselves with those elites. This has usually only resulted in actual dictatorships in Latin American left-populist countries (cf. Maduro in Venezuela, Ortega in Nicaragua), but the most common presentation globally is as right-populism which strengthens enough to begin changing the country's constitutional framework (true for all of Modi/Orbán/Erdogan) in ways that tend to strengthen its own hold on power.
Part of the danger here might be that many voters are inclined to vote for people or groups who have histories of being 'really' opposed to the establishment, which might select for extremists because anyone who wants to change the system but is not an extremist will probably choose to work within it. (This explains the military hostility, since it is usually the loudest defenders of the status quo who seek military careers; this may be far-right in certain contexts, but it is conspicuously not the kind of far-right which is gaining power, which is moderately to greatly hostile to status quo politics and therefore predictably has conflicts with the military. 1920s and 1930s-era fascists, who wanted to conquer neighboring countries, were able to get around this by explicitly giving the military more power and making it higher-status, but this would be very counterproductive for today's far-right governments.) Thus, today's paradigmatic parties are ones like the National Front in France (which originated as a Vichy-nostalgist organization) and the Sweden Democrats in Sweden (...originally very literal neo-Nazis), both of which moderated in response to getting closer to power. It's very noticeable that taboos on cooperation with both of these parties broke in 2022, and the same year Brothers of Italy (for whom the taboo broke long ago) became the dominant party in the Italian government.
The cause of the trend appearing at once in many different countries is tough to pinpoint; it may be that some degree of authoritarianism has always been popular and modern communications networks have made it easier for ordinary people to organize. (I think David Shor has written that in the modern social-media environment the civil rights movement may have failed, for instance). The sum of all authoritarian tendencies in developed democratic countries may be constant (it feels kind of tough to say that 2010s/2020s Republicans are really more authoritarian than the government which did MKUltra/Tuskegee/suppressing dissent with the fairness doctrine), and it may be that it is now harder to get away with that sort of thing unless your supporters really do not care, in their heart of hearts.
Hopefully this comment is useful.