I've probably had hundreds of conversations with people who will say "well, not everyone can afford to move town" or "not everyone can afford to take a week off work" or whatever else.
That's an enormous handicap - you're basically a slave to your current job, and if it tires you out enough that you can't train/learn/do other productive work outside of it, then you're stuck.
Personally I grew up with essentially zero, and pretty much self-enforced level 1 upon myself until this chart would have me at level 4.
People talk a lot about how certain startup founders aren't really risking anything because they start out with a safety net. You can create that safety net for yourself, with a little luck along the way, provided that you're sensible.