They may be brilliant, driven, creative, hardworking people, but they Just. Don't. Have. Scars.
They never really had the chance to run face-first into reality, while still in a position where the stakes are low, and there's more experienced folks around, to help them get back on their feet.
Their first mistakes are disasters, because they have it all on the line.
In the past, the older folks had the money and power, but were often locked up by caution, and lack of creativity.
The younger folks had the energy and creativity, but not the sense of mortality. They needed the money and power from the older folks, and the older folks needed that creativity, and, for lack of a better word, recklessness, that could drive their investments forward, so they had to work together.
These days, it's pure recklessness. The first forays into shipping are "bet the company," so failure is an E.L.E.
I have a pretty heavy-duty résumé. I've been shipping (not just "writing") software for over thirty-five years, and have a fairly big portfolio (that really only covers the last ten years of my work, and just the open-source portion of it). I've written APIs that have lasted 25 years. I do good work, and can prove it.
They would contact me, breathless and excited by my CV, then ghost me, as soon as they figured out that I was over 40.
I guess that math isn't a big requirement to be a recruiter. The industry must be awash in 30-year-olds with 35 years of experience.
These days, I just make it clear that I'm older, and they stopped bothering me.