I mean, sure, if it's likely you are going to spend your life making very little money, then sure, avoiding debt at the outset should be paramount. But getting some education, for most people, is probably the strongest thing they can do to decrease the chances that they will spend their life making very little money. I would argue that the next biggest thing you can do is to surround yourself with people who are going the direction you want to go.
I think the social and personal development sides of a metropolis are also pretty great. If I want to, (and I do) I can spend all day around people who are smarter than I am. I mean, substitute in your own figure of merit; no matter what you value, if you are in a dense area, chances are, you can find a group of people you can surround yourself with who have a lot of it.
This isn't just because of the migration of people who are financially able into the cities... this is also because there are more people of any type that are within your reach; there's a much larger and more diverse pool of people from which to pick your friends. If you are the average of the three people you spend the most time with? you want to be in a dense area where you can choose three really amazing people.
My own impresison, as someone who makes a good living without a degree, is that where you live actually matters a lot more if you don't have a degree; the difference in sysadmin jobs between silicon valley and less dense places is absolutely huge; much greater than the difference, say, in doctor jobs or even software engineer jobs.