Outside view of your 1 2, 3 and 4: most people end up in trajectory number 4, so thinking this is the least likely scenario needs some really good evidence.
In particular let's look at 1: How do you plan on an event that has a reasonable probability of not happening in your lifetime, and about which you know relatively nothing (if we could well predict what will happen on the other side, it won't be anything like a singularity).
Who is to say that a singularity results in happiness for everyone -- even for a positive one? From the standpoint of someone sitting in the 18th century, flipping into life today would be like a singularity -- even poor people have luxuries not dreamed of 200 years ago. That said, it's a lot more pleasant to have money or marketable skills than not, even in the cushy rich world. Try being actually poor in the US to see what it's like. See how well you can live on $800/month (a typical very small social security benefit) with no savings and no family support.
For 3: from your perspective right now, there doesn't seem to be any reason to stop working. Past a certain relatively young age, however, anyone who is not good at selling themselves, developing a network, or established as a well known expert in their field will find themselves at a huge disadvantage in the job market, and may no longer be able to get interesting jobs for good pay. At that point, someone who followed the moustache plan in their 20s and 30s doesn't really care -- they can try as many new startups as they want and give the finger to the "norma"l job market, never worrying about whether they will have enough to eat and live in a comfortable home.
If you have never saved any money, you may end up forced into plan 4 in your 40s often at jobs that are uninteresting and do not pay very well. I've seen it happen to a lot of smart people.
Do I think it's worth trying startups young? Yes. And realistically a few failures in a row will probably sap your will to start a new one in any case, so there isn't that much risk of getting past easily hirable age, so I recommend looking to do it early on.
That said, whenever you are making good money, some long term savings is a good idea -- money gives you future flexibility, and the hedonic hit you take to save 15-20% of your money when you are making a solid middle class income is barely noticeable.
Outside view of your 1 2, 3 and 4: most people end up in trajectory number 4
I'm not sure how to word this well, but "most people" haven't lived in the year 2080. Because of a) the possibility of a singularity and b) the law of accelerating returns, the "most people" that you refer to doesn't seem like an appropriate reference class to me.
In particular let's look at 1
I think you're downplaying the chances that a singularity does happen in my lifetime. 90% of experts seem to think it will.
Interesting point abut 200 years ago thoug...
I'm 22 years old, just got a job, and have the option of putting money in a 401k. More generally, I just started making money and need to think about how I'm going to invest and save it.
As far as long-term/retirement savings goes, the way I see it is that my goal is to ensure that I have a sufficient standard of living when I'm "old" (70-80). I see a few ways that this can happen:
Median optimistic year (10% likelihood): 2022
Median realistic year (50% likelihood): 2040
Median pessimistic year (90% likelihood): 2075
- http://waitbutwhy.com/2015/01/artificial-intelligence-revolution-2.html
And even if they're wrong and there's no singularity, it still seems to be very likely that there will be immense wealth creation in the next 60 or so years, and I'm sure that there'll be a fair amount of distribution as well, such that the poorest people will probably have reasonably comfortable lives. I'm a believer in Kurweil's Law of Accelerating Returns, but even if you project linear growth, there'd still be immense growth.
Given all of this, I find thinking that "wealth creation + distribution over the next 60 years -> sufficient standard of living for everyone" is a rather likely scenario. But my logic here is very "outside view-y" - I don't "really understand" the component steps and their associated likelihoods, so my confidence is limited.
Anyway, I think that there is a pretty good chance that I succeed, in, say the next 20 years. I never thought hard enough about it to put a number on it, but I'll try it here.
Say that I get 10 tries to start a startup in the next 20 years (I know that some take longer than 2 years to fail, but 2 years is the average, and it often takes shorter than 2 years to fail). At a 50% chance of success, that's a >99.9% chance that at least one of them succeeds (1-.5^10). I know 50% might seem high, but I think that my rationality skills, domain knowledge (eventually) and experience (eventually) give me an edge. Even at a 10% chance of success, I have about a 65% (1-.9^10) chance at succeeding in one of those 10 tries, and I think that 10% chance of success is very conservative.
Things I may be underestimating: the chances that I judge something else (earning to give? AI research? less altruistic? a girl/family?) to be a better use of my time. Changes in the economy that make success a lot less likely.
Anyway, there seems to be a high likelihood that I continue to start startups until I succeed, and there seems to be a high likelihood that I will succeed by the time I retire, in which case I should have enough money to ensure that I have a sufficient standard of living for the rest of my life.