There is one factor here your forgetting: In the D&DE classes are not necessarily "better" or more "powerful" but merely preferred by more players. There could be many reasons for this: lapsed players who enjoy the concept of the diverse new builds, new players not wanting to learn to play a fighter completely different than what they learned in Essentials, 4e veterans who like the new way of doing things, etc. All of these people could lean enough on WotC to make them abandon the initial 4e versions of these races/classes and institute new powers/builds for the "Essentialized" versions. At that point, you have a 3.0 ranger; not dead insofar as they can't be played using the newer rules, but not mechanically supported any longer.
So... you're saying that if the majority of people prefer one build that wizards will start supporting that build.
Isn't that what they SHOULD be doing? Shouldn't they be designing for a game people are enjoying?
My money though is that Monster Vault nearly invalidates MM1 Except for maybe a dozen or so monsters (like Orcus, for example). Sure, the goblin minion will be a Goblin Noseflicker rather than a Goblin Cutter, but it will be the de facto goblin minion going forward...
What is the "de facto goblin minion" though?
I'm honestly confused on what you mean here. You have a book full of monsters to use in your game, how is it invalidated by another book full of monsters?