$20 an hour is different all over the country. $20 in Vegas is way better than $20 in Cali or Portland. These things cannot be set in stone. Zone economies are different all over the place, even in the same states. IMHO, most making $20 or less an hour aren't living by themselves. Shoot I didn't make $20 an hour until my 2nd Job out of college. Now I'm almost making double that due to moving and having to find new jobs, which paid me better as I gained more and more experience. I also was able to choose a career no one likes. Being young is tough, and you can either cry about it, or get to work and gain experience so you can move up. The majority of kids making $20 an hour are doing just fine. Its the ones who have no friends, no family, or anything to help them split rent. Most cars they have are purchased outright. Those in their 30-40s plus still making $20 an hour should probably look for another job tbh, there is potential to get something at 25.
Here's the truth. America is the land of opportunity. Opportunity doesn't mean sitting around begging someone else to do something. It means you have to go out there and get it, prove yourself, and eventually move up. Opportunity doesn't mean easy. But it does eventually help you find success if you go after it.