Windows NT on 600MHz machine opens apps instantly. What happened?

It is such a pain to write Win32 code that you didn't have time to add all the features that would slow down program launch.

As cynical as this comment may be, there may be an element of truth to it. If it is time consuming to add a bunch of visual effects and transitions, you aren't likely to spend time doing that if you could instead be adding useful features.

I know you probably meant it in jest but as someone who wrote a bunch of desktop apps at one time, it was actually easier to develop desktop apps in tools like Delphi in the 1990s than it is to develop apps now.

For me, VB6 was the pinnacle of Windows desktop app development. When I first starting building web sites/apps it was such a huge step backwards.

It was/is a huge step backwards in terms of DX, but an infinite step forward for distribution. Distribution is the ONLY problem, which is why the shift happened.

Try Xojo Web, pretty neat tool with VB like web builder.

But, Delphi existed mostly because of the terrible default Microsoft DX. Writing pure Win32 was indeed pretty awful (and still is).

Most software is not developed by a single person and adding animations have very little overlap with most functionality, so it is almost completely parallelizable.

Absolutely, which is why I (we all really) put up with the mess that is/was web development.