I think what you're seeing is this: Apple Watch is a very popular, yet expensive, mass-market gift to many... at the lower end of the price range ($399 or under). At the higher end of the price range ($499 and up), it's more of an enthusiast device, for the minority of people (like the ones on this forum). It's a fairly expensive "want," not a "need." All variations are pretty durable, so people keep using them for many years. I'd guess the upgrade cycle for an Apple Watch, especially a low-end variation, is pretty long (on the order of 3-5 years). Consequently, the majority that have been purchased over time don't have the Always On feature: they were purchased before that feature was introduced, or they were variations at the lower-end of the price range.
I'd wager that very few people intentionally switch off Always On (<1%), simply because it's a default and most people don't even know it's an option to do so. I leave it on because I like it, and battery life on the Ultra is no longer a limiting factor. To me, a black square on my wrist with nothing in it seems like dead space, and I do frequently sort of glance at the time without having to move my wrist or body. Wake on wrist raise always felt like a (clever) stop-gap to me.