Rob credits the negative reaction to 4E being because it changed both the rules and the setting, saying that it might have been better received if the setting stayed the same while the rules changed.
I think there's some nuance in this.
One of 4e's problems was definitely that it changed the rules and the setting...
and then still called itself D&D. One of the loud complaints (that I don't personally agree with, but saw a lot of) is that this game wasn't the D&D that people wanted and expected and desired. It was something else. Something alien. Something not "for" people who already liked D&D and just wanted a better D&D experience. The old "If they wanted to make a new game, they should've done that, and left D&D alone!" argument.
I don't think keeping the setting the same would've solved that problem. That problem is also a rules problem. If it doesn't "feel like D&D," in the play of the thing, then we still have the problem.
That particular problem grew out of something like this:
problems with D&D that 4E should be designed to fix
What they came up with to fix didn't line up with what most people thought D&D's actual problems were. If Noonan was the only person coming up with this, then Noonan got it wrong in a big way. If this was the genesis of a new edition, it's not surprising that the edition that grew out of this was divisive. Not everyone agreed with Noonan on the problems that 4e needed to fix, or how 4e fixed them.
I think 5e has learned both of these lessons reasonably well.
First, that a good version of
Dungeons & Dragons is not the same thing as a good version of a fantasy TTRPG. The fact that it is D&D carries with it certain ideas and desires that need to be met by the designers that constrain the design in various ways. If you're selling to D&D fans, those fans need to see the game you're making as D&D.
Second, they're committed to getting feedback on their intended design paths. They want to see what the audience of D&D players sees as D&D's problems, and are perhaps less interested by one internal stakeholder's perspective. Though I imagine that perspective still matters, it's also subject to testing and validation with the actual audience of the game (or at least a fairly dedicated slice of the audience).