I suppose you are right. I worked with MFC/C++ and COM and it was horrible. Delphi and C++ Builder things were nicer to use but fell by the wayside, particularly after Borland lost their focus and didn't bother supporting VCL correctly in themes and also had major issues with their C++ compiler. They suffered a brain drain.
I remember Windows Explorer opening swiftly back in the day (fileman even faster - https://github.com/microsoft/winfile now archived sadly) and today's Explorer experience drives me insane as to how slow it is. I have even disabled most linked-in menu items as the evaluation of these makes Explorer take even longer to load; I don't see why it can't be less than 1 second.
Anyway, I do recall Netscape taking a long time to load but then I did only have a 486 DX2 66MHz and 64MB of RAM.... The disk churning did take a long time, now you remind me...
I think using wxWidgets on Windows and Mac was quite nice when I did that (with wxFormBuilder); C++ development on Windows using native toolkits is foreign to me today as it all looks a mess from Microsoft unless I have misunderstood.
In any case, I can't see why programs are so sluggish and slow these days. I don't understand why colossal JS toolkits are needed for websites and why the average website size has grown significantly. It's like people have forgotten how to write good speedy software.