I don't think that's necessarily true, though. Even back in the pre .NET days, when Microsoft pretty much did have a monopoly on PC desktops, Visual Studio (not VSCode, but its full-fledged big brother) had pretty awesome DX.

And having a standard UI layer (like WinForms) made GUI development way way better for both the developer (who could drag and drop shapes and easily align frames and tabs and buttons and such instead of having to try to wrangle CSS) and the average user could have standard UI looks & feels across many different apps.

The openness of the Web led to its popularity (and my career), but then every company ended up making their code style, IDE, APIs, UI layers, etc., leading to extreme fragmentation in both DX and UX that to this day is still a mess. Of course I still prefer this over a closed Microsoft monopoly (or an Apple one), but it's certainly made for a lot of unnecessary reinventions of the wheel.