Don't modern versions of Windows do the same? For example, I clearly remember that the Windows 10 installer first launches a Windows 7-like environment.
There have been iterative substantial improvements to the NT architecture since Windows 2000 and later with Vista (where the UAC model started, rather poorly).
Really? Windows2000 (which was based on NT) hit the sweet spot for me. Anything earlier than that seemed too buggy, and from there onward just seemed to devolve into a bloated mess of unrequested "features". (The very reason why I have been using Linux for 20+ years now as a matter of fact.) But yeah to be completely fair I suppose not everything they have produced since has been crap. There have been some innovations here and there...