Yeah you definitely make some great points there. Come to think of it, my last trainer (who is maybe in her late 30s, early 40s) was already quite selective with what she’d take on training-wise. I asked her about it once, and she just had too much to lose if she got injured by a young horse being dumb. A HCOL area, coupled with an already small margin industry means that getting injured could easily cost her her barn (which she had only just been able to afford in the last year or two anyways). From a realistic standpoint, it was just safer to focus on giving lessons, boarding and taking kids to horse shows than to bother making and selling horses.
Compare that to my current trainer who is older, but still hops on greenies from time to time if they happen to pass through her barn - she’s working out of a property that her family has owned for decades, and she’s got other sources of passive income with rental properties and some part time work she does. She’s not dependent on her barn to put food on the table, and it’s not going to go into foreclosure if she gets injured. Her overall risk is much much smaller.
Personally, I’d love to pull something off the track, put a few months of work into it and flip it, but even in our low cost of living area, board is still around $650/mo. That, plus any vet/farrier/dental costs, and of course the cost of the horse upfront - I’m not sure I could even break even, let alone turn a profit.