And I am 100% convinced it would have died in obscurity, with 95% or more of D&D players never even looking at it, let alone playing it. Putting it in that position would guaranteed kill it off dead, even before you consider that being "D&D the Adventure Game" would have meant it got zip-zero-zilch-nada additional support after publication.
"100%" tells me that you're just not willing to take that chance. You lack faith that anyone else could possibly want something different, or that you won't have anyone to play things your way. 4e already proved that there is some section of the population that not only accepted the radical changes and challenges of a newly designed D&D, but a good amount of that population still has fond memories and continue to enjoy it to this day. Not only that, but more people are rediscovering it again and putting a more positive light on their retrospect.
I mean, as it stands, at least half the people who criticized it never played or even read it either, given the pernicious and dead-wrong "criticisms" that were the stock and trade of the edition war (and thus still linger with us today).
Maybe you need to stop focusing on those discussions, and the people who decided they won't be changing their minds anytime soon. Surely you aren't going to miss those people at your table.
Also? I'm certain you did not mean it, but...well, there's really no other way to read your distinction there as anything other than "4e isn't for roleplaying." Which is both untrue and deeply, deeply frustrating, because that, too, is a longstanding insult without any basis, other than efforts to exclude 4e from being "true" D&D.
I might have been insulted if I wasn't genuinely concerned that this was coming from you. If you think that was ever my position, then I have to believe that you have been fighting this war for far too long. I'm starting to think you are trapped in your own private war, doomed to see enemies and offenses everywhere. Stand down, soldier.
I'll just say this.
The biggest problem with D&D is this idea that it is THE RPG for everyone. But the term "RPG" itself has been so many different things to different people, especially those who market their products with only enough traits to capitalize by adding "RPG" on the label. It is storytelling. It is make-believe. It is fantasy. It is simulation. It is strategic combat. It is wargaming. It is miniatures. It is theater of the mind. It is turn based. It is freeform. It is sandbox. It is open world. It is railroad. It is narrative. It is procedural. It is dice. It is cards. It is both. It is a game. It is a way of life. And so on. More importantly, and specifically to D&D, it tries to be everything (and more) to everyone. And there is the biggest problem.
Very few people want ALL of that in their game. Most want only a few of those things in varying degrees, but not everyone wants the same things. We can't just agree that we all like RPGs without a declarative statement to qualify the kinds of RPGs we prefer, or even the styles we like to play. Yet, the company must somehow cater to all, or risk losing customers to other (possibly more suitable) games.
Getting past all that, we accept whatever version suits us for the kind of game we want to play. We just need to find players who will also accept that kind of game, otherwise we will never enjoy our games because it is meant to be played with other people. Now we discover that different people have very different ideas and tastes! But shouldn't the game tell us how it is supposed to be played? No, but it sure would help a lot if it told everyone else that MY WAY was preferred. Or, better yet, that it was the RIGHT WAY! (You see where this is going?)
When I suggest that 4e could have been a different kind of D&D game, I also meant it could also be a different kind of RPG. But there can only be ONE D&D RPG at a time, at least according to... I don't know what to call it, actually. Popular opinion? Common sense? Corporate mandate? It's not important.
What if 4e had been "a D&D roleplaying game" rather than "THE D&D roleplaying game"? Obviously, it would not have been the 4th Edition, but I think a lot of people would not mind so much if it meant having an alternate version of a game they liked alongside whatever constitutes the traditional game that is suited to other people.
Just imagine that for a second. 5e comes out as 4e, while 4e is released as a different kind of D&D. What is it, exactly? I don't know. But nobody ever finds out by not doing anything. We are stuck with whatever someone else decides to put in front of us as we continue revisiting the same discussions, and the same arguments, with the same people.
But you go on fighting the good fight! Maybe someday you'll get the kind of game with the kind of people you've always wanted. But you'll probably have to let your guard down just a little. Or find people who don't live on online forums, or haven't played anything before 5th edition. Whatever you do, good luck!