Are these "intelligent" investments? Or just complex adaptive systems which are theoretically digestible by you but you don't even bother?

Honestly, I wouldn't bother putting my money into a 401k - I would stash it away, let a little rot away with inflation and use it to start a business that provides real people with a real product and pray. That seems like a more sure-fire way to get across the line.

Ostensibly, that can be thought of as a more extreme version of your "pick an index and stick in it" approach. The reality of it is that we don't know which one of these choices is the right one - it may be so that cryptocurrency will make you trillions! Or that the Roth IRA will have 70% of the people who stick their money in it as actual millionaires despite them only making $70k a year for 30 years.

Factually most businesses don’t make it past the 5 years point for different reasons which are not always even solvable by the the starting team. An example would be the market moving at a time where you don’t have enough available capital to adapt. The alternative is doing something relatively predictable and safe like a corner store or a bakery. There is good money to be made there but probably not much more than by doing a well paid engineering job for most.

Don’t get me wrong. Starting a business is a bet in yourself which is always good. I think people who are interested in the life style should definitely do it, just not by using all their retirement savings.