Is Hollywood propaganda the reason so many men nowadays fall for the "men peak in their 30s" cope?

I don't know who this POOFTER is but he couldn't be more wrong. Life's what you make of it. Rock.

Yeah when you start getting closer to 40 you need to work harder at taking care of yourself. That’s no surprise and doesn’t mean your best days are behind you and you can’t attain your peak alter on.
Youth always looks better when you are older because as the saying goes youth is wasted on the young. But in terms of career, confidence, sense of belonging, mindfulness, contentment/fulfillment, sense of purpose and so on I’m 40 and feel like I am really hitting my stride. Sure my hairline isn’t what it used to be and I feel like it takes a bit more time to rebound from injuries but the truth is I’m in better shape now than ever before but that’s because I actually think about what I eat and go to the gym now.
How you age is largely up to you. I am a prof and my professional and social scene is generally made up of highly educated and upper-middle class people and they tend to take better care of themselves than the blue collar parents I know. This is a generalization but what I’m getting at is I see a very big difference in how certain people age and attention to diet, exercise and mental well-being is massive. If OP’s slob’s trajectory is on the decline that’s on him.