I'm kinda in the same boat and feel like I've done the whole 360 on domestic first class. Before the pandemic I was usually just a silver so never got CPUs and was content with economy+. Then during the pandemic, I ironically had to fly more for my work, and was able to snag mileage upgrades and cheap polaris seats on my EWR-SFO flights. At first, I was like "this is amazing!" and would be disappointed whenever I had to sit in the back. But now, while I still think Polaris is nice, the "ooh! ahh!" shiny new thing factor is gone. And with the lack of upgrades and much more expensive fares, I've been almost exclusively in economy for the past several months. And you know what? It's not so bad. I manage to get a couple hours of sleep, I can still use my laptop when needed, and honestly, the burger they sell in economy is better than the meal they serve up front. The soft product is not that big a difference, and with regards to the hard product, especially if I happen to get an empty seat next to me, I don't feel like I'm missing much. I'm rather glad to be saving the $1k for the 6 hour flight.

I still religiously apply my PP and hope for an upgrade (which never comes now), and if the price differential is <$500 then I'll still consider buying the polaris seat. But otherwise, I guess I've gotten used to being a commoner again :-)

The other long term issue I always wonder about, is that, it's easy for airlines to view free upgrades or mileage awards as a cost. But how do they account for the fact that for every one upgrade or award seat they "give away", there are X number of people who chose to fly United over some other airline, and build status with them, precisely for the chance at those upgrades and awards. That is, perhaps they could sell that seat for $500, but once elites realize they don't have a chance for free upgrades anymore, they might lose more than that in lost ticket sales as lucrative business passengers move to other airlines. For example, I think that Delta for the longest time wasn't a preferred airline outside of its fortress hubs because its mileage program sucked so bad that most business people preferred flying with United or American so they could get miles that were actually useful. IOW, airline execs seem to think it's great that people accumulate all these miles and PP and status, by steering thousands of dollars of spend their way, but then think it's BS when we actually try to use those perks. They may get their wish and have people finally stop accumulating these points and just pay for whatever they want. At which point, they'll find themselves competing with Spirit selling their (surprisingly cheap and comfortable) Big Front Seats and wondering why no one is paying a premium over that...