Microsoft stuff was going for fixed screen size/resolution, fixed layout, and using a quite limited set of controls.
Web browsers try to be accommodating by default - any screen size (including mobile), zoom built in, and significantly more powerful control primitives that allow enormous flexibility in the way to design things.
If you're building forms applications that only need to work on a PC, the old way was certainly easier, and in fact, Microsoft has WebForms (regular ASP.NET - not MVC or API) that is pretty similar (and doesn't horribly break down so long as you color within the lines, so to speak).
Try to imagine your vb6 app being able to scale down to window the size of a phone screen, and how the WYSIWYG editor for that works even work - I imagine it would be fair to describe it as "hot garbage" also.
Web works across everything with little to no extra effort, whereas native app built with WYSIWYG UI builder is going to be constrained to certain hardware and take extra effort for handling display variations.
I say this because it took me zero effort to use due to how intuitive it was to get started...
MS tools are still here for those of us doing native Windows development.
Also the Apple and Google GUI tooling for their mobile OSes are quite good.
Much of the complexity of web design is not in the tools; it's in the fact that users don't expect a standard whatsoever, they just expect their UIs to be as slick and customly designed as magazines. If every website was written using the same standard, predefined set of widgets and components, the complexity would disappear.
Users expect every website to have a unique identity (unlike anything built with WinForms), that is what creates the complexity.
If you actually use something like bootstrap, your website will look unoriginal, but it will be dead easy to make.
yarn/typescript and (though some days I hate it..it has gotten better) webpack largely make it feel sane(r).
That said getting to a point where I was comfortable with all three was insanely more complex and time consuming that picking up Delphi 6 was in the early 2000's.
Shrugs, the beast is what it is until someone does something better.
This lack of support for anything other than hardcoded absolute layout is exactly what made it so simple and easy to use. It's the equivalent of doing document layout by padding with spaces - it works for simple cases, and it's very easy to teach people, but it's a mess for anything even remotely complicated.
That's largely a non-issue to me. If I need anything fancy, I'll draw it myself. The simple stuff ought to be simple.
> As a result, things break as soon as you try to make an easily resizable window
Au contraire! It is much easier to make a resizable window when you are in full control of how nested widgets are resized along with it. That being said, some automation is fine (e.g., how MFC resizes views in response to their parent frame being resized) as long as simplicity isn't lost in the process (I'm looking at you, CSS).
Properiatery low-code tools built over the web are a better starting point.
