You haven't played the game.
If you insist, but I think you might be in a minority when saying that, particularly when stating outright that the RTS genre died because, basically, it was overtaken by games that require a much lesser time expenditure (which, honestly, I don't think is true, and I provided examples to the contrary) due to people generally becoming dumber, which... just isn't an useful statement (mostly because it's very biased and emotional) to make when gauging this phenomenon. You also insist that only 8 player modes have any legitimacy, which I think is a reductionist attitude because that essentially implies that a 2v2 or 3v3 brawl between highly competent players is worthless compared to a 3v5 slugfest against the AI where - as much fun as the mode is - the outcome is generally preordained when the players have the know-how and there's plenty of cheese techniques to fool the AI, like in pretty much every game.
the 4 vs 4 is a REAL game of strategy and tactics, particularly when you have a range of expertise in both teams.
I never denied that it takes considerable skill to play in such an environment. But I don't think that it denies legitimacy from the other game modes that are available. I also don't think that the complexity of the game mode means that you can't systematize and standardize certain things, like you could in any other game. There's a shitton of complexity left in Blizzard RTSes as well, and a meta game for any game mode you can think of, but I will still be the first to admit that even if the meta evolves a fair bit even today (through certain adjustments and ideas), it's still mostly set in stone.
In fact, I decided to educate myself some more, because, hell, why not, AoE2 is a very good game and I actually enjoyed learning about its intricacies in highly advanced modern online play as I prepared to respond to you properly. If the popular high level AoE2 streamers are any indication, online players still rarely, if ever, get games that last over an hour. That ZeroEmpires guy I pointed out earlier considered a 52 minute 4v4 game to be
"pretty long" and he even managed to fit in 4v4 games that were, on average, around 35 minutes long.
Given your highly emotional and anecdotal account and a note that you generally no longer keep in touch with the same group since 2009, I'd insist on maintaining that your experience isn't the norm. I'd also refrain from carrying on an attitude of superiority about the way you play your favourite games (something that I try to do myself, as I honestly respect dedicated players of all games in this noble genre, especially since I played and enjoyed a lot of them myself, even if I ended up returning to Starcraft), because this is a thread where we talk about why RTS games have fallen out of favour and not having a war about whose favourite RTS is the best.