Over the last few years, I've noticed four trends:
-Most obvious is the rise of spend-oriented FFPs, both in the US and in Europe. This has dovetailed with the rise of credit card-generated miles (even ignoring the wacky distortions of 2020-22) versus miles actually acquired via flying. In the US, one can get all the way to top tier status (aside from the invite-only tiers) on four of the six-or-so largest carriers (DL, AA, B6, and WN). AS and UA aren't quite there (AS has a hard cap; UA has a "soft cap" in the form of per-card limits (though someone who has the old PresidentialPlus personal/business cards alongside one of the bigger new ones could get there) plus a requirement to actually fly 4 UA flights/yr).
--Own-metal flying requirements have also slid away. As of this year, as far as I can tell most of OW doesn't have the requirements, or only has them at a low level (IB) or very high level (BA, AY). I think in the US the only holdout here is UA (I am admittedly ignoring Spirit, Frontier, and Allegiant - partly because one or two of them seem to be on death watch due to shifting market trends and partly because they're not in-alliance).
-Next, over in OneWorld, a bunch of airlines are suddenly using Avios. It didn't stand out when it was just IB-owned airlines (that was no different than e.g. the LH group consolidating the program for the airlines in their group), but adding a few others changes the "feel" here. The weird bit where AC briefly sold off (and then bought back) Aeroplan also stands out here.
-Third, the rise of "equity entanglement" across airlines jumps out. DL, AF/KM, and VS are tied in a knot. Qatar and IAG are tied up. And of course, there's LH's clump of airlines and so on.
-Finally, I feel as though there's a general coordination of status requirements. Admittedly, some of this is driven by BA's new tiers looking a lot like AA's, but DL and UA aren't horridly far off on this front.

So one thing I have to wonder is whether we might eventually see a move within one of the alliances (or more) to just develop a full-blown alliance program (be it an ERM/Bretton Woods-style full interchange system, one of the programs just swamping the others (e.g. AA adopting Avios), or a new thing getting fully overlaid)? I presume it would be mostly spend-focused on both sides (earn/burn), if with some possible oddball exceptions here and there.

i will be concerned about anti-competition regulations if airlines are overly integrated. but i can see e.g. AA adopting avios as i expect that to increase the value of their ffq, so it can boost their profits from things like co-brands cards and eshopping portal.

Seems inevitable that a long-term Alliance FFP would just degrade the experience a lot more - Imagine a UA loyalist getting treated better on LH than an LH loyalist because *A spend/flying is all that matters. There's also arbitrage opportunities where you could get status for cheaper by crediting your spend to an FFP from a relatively poorer country. Or if the spend has to be equal (in currency) and not adjusted for domestic purchasing power, then flyers in the latter might as well forget about status. At that point, it's as good as merging the alliance into one big airline, which is more anti-competitive if anything.

I also try not to discount American exceptionalism, even if it's just an FFP program, to switch to Avios, maybe an option to do 1:1 exchange with Avios at best. However, I feel the concept of partner awards and sweet-spot arbitrage opportunities there would disappear or become extremely rare if this change were to happen. Same goes for some programs absorbing fuel surcharges while others don't. Good to keep FFPs somewhat local imo.