>Windows 7 was effectively just vista but enough time had passed that the required hardware to run it was easy to get a hold of.
Not really, Windows 7 had a lot of work poured into it, fixing Vista issues. Even first public betas of W7 were more polished than any of Windows 8..11 releases. That includes work on minimal amount of "noise" notifications, driver issues, speed, design etc
Basically all of those fixes were applied to Vista before the 7 beta. There were some rough parts to Vista's released, but a lot of those were polished by SP1 and SP2.
The reason the W7 beta went so well is because it was already just based on later versions of Vista.