> How many applications created in the last five years use Win32 for anything but creating a top-level window (usually via Chromium/Electron)?
I think that you're in a bubble for that one. Many business domain-specific applications are still directly written against Win32 even today. UWP didn't manage to catch up for now either.
Electron usage is mostly only in startup-y apps and some IDEs.
No experience is universal, so I'm curious in what industry you encounter Win32. Or do you mean WinForms? I often work with industrial manufacturing companies in Europe, with a mindset about as far from that of Silicon Valley startups as you can imagine. You usually won't find Electron there. Many "legacy" projects are in WinForms. But for newer stuff, I see lots of WPF and Qt projects, both of which don't use native controls.
Outside games, most modern Windows applications, specially in the areas you mention, I have also seen WPF/Qt, with plain old Win32 just as glue for underlying OS APIs.
There are still some odd ones that keep doing MFC, or enjoy a mix of Delphi/C++ Builder.
The only old style C Win32 applications I have seen in the wild during the last decade tend to be surviving applications from the 90's, done by companies not so much into Windows C++ frameworks.
I think that you're in a bubble for that one. Many business domain-specific applications are still directly written against Win32 even today. UWP didn't manage to catch up for now either.
Electron usage is mostly only in startup-y apps and some IDEs.