I'm 33. I've been doing this for a total of a few weeks now. The way it came about was quite accidental: I was working for a B2B finance startup, and quite happy with it -- it's a laid back, chill job. The nice thing about finance is that no one's heart is in finance. Mostly that manifests itself as finance companies becoming obsessed with money and taking advantage of their coworkers. This company took a different approach -- everyone is focused on work/life balance above all else.
My heart happens to be in ML. So when an ML opportunity came along, I went for it. Things worked out. They offered a full time salary position for equivalent to what I was already making. I told them "I understand that you're not able to afford market rate for ML engineers -- let me know if that changes! In the meantime, why not do a contract for that rate and see how it goes?"
They protested in the usual way, but the problem was, they needed me. Both companies need me, and I'm effective at both.
I make roughly three times the average SV startup salary. I don't get sick days, which is the only part that sucks. But -- regret? You overestimate how much work this actually is.
The best part is the work itself. I get to design some cool-ass banking infrastructure while also doing some cool-ass ML work. And the whole reason I'm doing all of this is so that my wife and I can have a baby, because IVF in America is $40k.
(I realized one day that if I worked as hard as I could -- or in my case, "at all" -- it wouldn't take that long to save up $40k.)
I would say it's a worse deal to gamble your life on startup equity in exchange for below market rate. The fact is, if you're someone who can get a job at FAANG in terms of skill level, you're underpaid at a startup, in exchange for the small chance of getting rich later on. I'd rather "sell my equity now" and take full market rate, as it were. But I don't want to work at FAANG, because FAANG comes with a lot of baggage that doesn't exist at startups -- which is the whole reason people take startup jobs.