Better?
No.
Taking out "in the world" tones it down, in the same way that taking the spikes out of a club tones it down. "Why would anyone..." is still a rhetorical question asserting that anyone who does is a dolt. You do the same in another comment: "Why would anyone make a lifetime commitment?"
Clearly, many people do get engaged, do get married, do make lifetime commitments. A majority of people, even, at least here in the West; I do not know how it is in Slovenia. (The disadvantageous tax regime you have in Slovenia was done away with long ago in the UK: married couples can elect to be taxed as separate individuals.) But saying "Why would anyone do such a thing" does not invite discussion, it shuts it off. If you actually wanted to know people's reasons, you would actually ask them, and listen to the answers.
Ok fair enough, can you propose a better way to ask?
I was interested in the following:
Why do so few people who want to get married question the wisdom of such a step considering its high costs and dubious benefits (in comparison to say cohabitation)?
Why do people in general want to get married? (this is different from the question of whether it is rational to marry)
Is it rational for most people who marry to do so?
I was not specifically interested in why Alicorn wanted to get married. I did want to provoke, maybe even shock people into thinking about it beyond cached thoughts.
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.