Such a generation of entrepreneurs have already been created; this past decade we see more startups (especially in tech, but not just so) than we ever did before.
To answer the actual question of why work for them instead of going at it on your own -- starting and building a business is hard. Even if you are capable of doing everything, and have the ambitions, it's still hard. Getting a job is relatively a lot easier, say what you will about tech interviews (btw, I do agree that tech interviews suck and are needlessly difficult). From that perspective, working for someone else is the easier way out, with a stable salary.
Other than that I agree with you, in most companies now you do have to play that culture game even if you're pretty happy with where you are now.
To answer the actual question of why work for them instead of going at it on your own -- starting and building a business is hard. Even if you are capable of doing everything, and have the ambitions, it's still hard. Getting a job is relatively a lot easier, say what you will about tech interviews (btw, I do agree that tech interviews suck and are needlessly difficult). From that perspective, working for someone else is the easier way out, with a stable salary.
Other than that I agree with you, in most companies now you do have to play that culture game even if you're pretty happy with where you are now.