No it is the right advice. The key is to improve yourself and make yourself more attractive. Accomplish more, work out, become more capable, make more $ etc.
I did that myself by improving my diet, doing kick boxing, get educated, interact more with woman etc. It worked.
If you don’t, you will end up with a partner who loves your fake persona and not you. Forcing you to continue living a fake life. That is not a healthy way to live.
That's probably what the "be yourself" advice was getting at. When you try to be someone you're not you show it through your body language, it looks contrived and it's picked up rather quickly. "Be yourself" was probably meant to be more like act less desperate for attention and more confident in oneself, don't try to impress, etc.. But I agree that it is not a good advice to people who do indeed need to improve.
"reach into the future and pull the best possible rendition of yourself backwards to now forthwith such that you can become thatself once thineself agrees that it is indeed thou that thou wishes to become"
Not sure about US culture, but this seems to carry a peculiar assumption that men should date around same age? Because I doubt most 20yo women in "midwest" are married with a kid or two. Maybe some bits of cultural bagage you need to shed there.
Might not have two kids, but not single is absolutely true. People here tend to find a partner pretty quickly in life.
Anecdotally, a friend is trying to date in her early 30s and basically has no dating pool. Not many single men in their 30s have a stable job, crime free background, and avoid hard drugs.
A good lesson for everyone: your life's time horizon isn't anywhere close to your life expectancy. There are things you need to get right before 30 if you don't want the rest of your life to be misery.
Since that's, after all, how everyone starts, obviously the cohort who thereafter asks for advice has found that not enough.