You should take a look at the thread on Ski Talk about the stem cells, if you haven't. I know there is someone there who seems to rave about a specific doctor with it that they have used. But yes agreed, it is an expense likely not covered by insurance and I'm sure not insignificant... but it could be worth it down the road if other things don't work and it is really hindering your activities. But perhaps it is only effective in certain cases as well.
I understand the concept of waiting for surgery and trying other things first of course, as well as not wanting to cause more issues later on, at least logic wise... I am not updated on the latest and greatest devices and longevity of these surgeries in 2025 admittedly. I just also feel it's an odd/crappy proposition how we have to wait until one is way older and therefore less likely to be able to even enjoy the improvements and pain-free activity as much as in younger years depending how long it takes to degrade to that extent and how debilitating it is along the way to that point I guess... IF the issues are so bad that it limits activities you want to do while younger, stronger, and more able bodied... that feels wrong. We should sit around and wait to rot away enough to intervene? And waste all that time as well? It just seems so counterproductive for anyone with a preference towards enjoying things now because tomorrow is far from guaranteed. Not to mention that major surgeries start to carry a lot more risk with advanced age too.
All to say, this is a very theoretical standpoint, and I am not actually saying anyone is right or wrong to explore, or not explore, whatever options in any particular timeframe. Of course, it is all very personal. I can only speak for myself on how I believe I would fall on the spectrum if it were me down the road in this position. I tend to find fault in this regard to Western medicine in general and how everything is so much more reactive than proactive. I find fault with this because in most cases proactive measures will always trump reactive ones, it is so much harder to fix what's broken rather than preventing it from getting broken, or as badly broken, in the first place. I feel like what Lindsay Vonne is doing exemplifies my thoughts on things really well... she was in pain AND unable to pursue the activities she wanted to and somehow it all worked out amazingly well to do what she's doing now with a partial knee replacement. I NEVER would have though that was a possibility for so many reasons. I am so all for that approach though and love how she went for it. Do it now, do whatever you can to enjoy it WHILE you can, figure out what's next when needed. Of course, she has way more access to the best medical team and a lot of financial resources as well, but the approach is 100% how I would want to approach it too haha. I know for a fact I would get pushback from some in my family who have a different outlook on these things, but that's my take regardless.