In fact, one of my favorite new rules from 5e is to reskin things however you like. I love it that I have that fluffy freedom.
Technically, it's not that new. Sure, in 2e you needed a spell (Sense Shifting) to re-skin magic, and nothing else was really up for grabs that way, but even in 1e there were some weapons that would stand in for eachother (the scimitar also included saber & tulwar - stuff like that). In 3.x it was official that you could describe your character how you liked - so race and gear could be re-fluffed all you wanted. 4e took that to 'powers' (spells, maneuvers, magic items &c), as well - fluff & crunch were virtually independent of eachother, as long as you didn't change a mechanical keyword (so you couldn't change a spell into a maneuver, for instance).
5e's actually back-peddled from that level of re-fluffing, FWIW, there's more places in the rules where fluff and crunch are 'entangled' with eachother. But you can still do it, even as a player, and the DM has unlimited license to mess with the crunch, as well (also not new, but not something that had not been much encouraged in the prior two editions).
We can all make up our own fluff without consequence, getting the crunch to work takes more of an effort to balance, and therefore many of us like to leave that task to the official publishers.
And the DM, of course - ultimately, how 'balanced' the game is, in play, is on his shoulders.
This seems to have given them breathing room to escape the short term profit motive, that in turn means the game could get a chance at a longer life. Which in turn, again imho, is reassuring to many that they are not buying into yet another soon to be previous version.
Yes. Stability is a perk of slow releases and lower investment.
That is growing the hobby.
Maybe slowing the rate of contraction. Growth generally requires riskier bets. DDI was risky, high-cost bid to grow the hobby, it crashed & burned. Encounters was a bid to grow the hobby, it didn't do so badly, and it hasn't been abandoned by AL, though it doesn't get the material support it used to. Besides, the only folks who are going to be gunshy about buying the next ed because the last few rolled so often or bloated so fast are established fans. New ones should be blissfully unaware of those issues.