But I do have ~1600h of purely multiplayer experience in HoI4 since the game came out and I've hosted probably close to 200 TS games. I've seen the rise and fall of the HoI4 MP community, the various metas, the evolution of various rulesets, MP mods and TS communities. Not to pat myself on the back, but I'd say I'm a pretty good source on the state of the MP community.
I admit I don't have nearly as much experience as you, however your authority is in question, as alot of your evidence is anecdotal.
So is mine of course, but I don't claim to be an expert.
By now though the MP community is so eroded that it's impossible to get a quality game during the week; you'll have to play in some Discord game with terrible majors and minors on both teams and with a garbage ruleset.
Or maybe people have things to do during the week and cannot devote a few hours to game because they need to work/study/sleep? It isn't vacation time anymore. Timezones also have an impact. Another possibility is of course that some people may have moved on to different rulesets out of preference.
PDX has said it takes them weeks of research, designing and testing to create a focus tree for a country. I think it was around 4-6 weeks to be exact, but I'm not 100% sure on that. Of course, the new fantasy trees aren't entire new focus trees, so it's probably safe to assume that each one takes only at least 2 weeks to finish. That however adds up when you consider they seem to be doing most if not all of the majors.
This patch will see the overhaul of two (2) majors only, as was stated in the most recent diary. There will be new trees as well, so I don't see how "it" adds up.
TfV and DoD are 60% and 75% SP-only respectively.
In TfV half of the new focus trees were fantasy stuff that's always banned in any decent MP game, and the remaining 10% are focuses that never get used because there's no point to use them. We got a new autonomy system (mostly trivial), some new strategies for a few minors and a nerf and buff to the early- and late-game Allies respectively.
In DoD half of the new focus trees were once again SP-only fantasy stuff, except this time 2/4 focus trees were on countries that are always banned in MP!

Some attempts at trying out new strategies for HUN and ROM were made but ultimately the meta didn't really change: HUN still spams planes and ROM still spams marines (and now also sometimes planes, what a change!).
By far the biggest and only really noticeable change to MP was that DoD gave us was the ability to rush late-war techs even earlier in the pre-war years; now 1938 instead of 1939! What a bargain for €10!
Your standards are not a universal metric, nor should they be. I have different thoughts on the trees and features, and that is hardly less valid than your opinions.
You also probably know that in the long-term, the Commonwealth nations are better off played historically, so it's obvious that Paradox is actually commited to making reenactment as appealing as possible (Just an aside). If you choose to exploit certain mechanics/metas, that's on you, not the game.
I know this might sound crazy, but I like to roleplay (as do some of the blokes I play with), even if it could be detrimental to my victory, because I derive enjoyment from that.
Well, I don't know what kind of games you play and I don't remember ever seeing you in the community. Although of course not everyone has the same name in-game as they do on the forums.
But when I'm talking about good MP, I'm talking about competitive 25-32 player TS games where all the majors and key minors have 1-3k hours, have been vetted and definitely know what they're doing. Said games also have good balanced and historical rulesets. There's also often a mod in play that makes the game more historical than rules alone can.
In my experience games with memes like communist France or fascist Canada do not make for a good game. And apparently I'm not alone in thinking that as such fantasy has been banned literally in every TS game I've seen basically since the release of HoI4.
My ingame/Steam name is AER0mat, and I haven't spent time in the circles you move in because I usually play with acquiantances and friends.
As for the rule sets I use, all of them ban any sort of exploits/excessive tech rushing.
You could say that. However I'd argue that if PDX listened to the "elitist" MP crowd, a lot of bugs, balance issues and outright silliness like minor countries having late-war tech well before the war or even nukes early in the war, would get fixed very quickly, thus prolonging the longevity of HoI4 in the process.
So you dislike certain aspects of the game (which is fine, I too have my issues with HoI 4), then turn around and claim that your select group of God's chosen people have the answers to these aspects and that it would benefit everyone?
(X) Doubt