There's no particular reason why native desktop software can't support online collaboration - online video games all somehow manage to support networked interaction while running on the desktop.

I'm working on electron-based desktop software at my job. We support macos, windows and linux. Building the same software natively would take 4x developers, move much slower, and require a lot more coordination. We would also not have access to incredible ecosystem of libraries and tools that we have at our disposal now. And if we wanted to develop a web version, to enable potential customers to try it out without installation, it would be a separate project equal in complexity to what we're already doing right now.

Of these points, I think that (almost) free cross-compile to the web is the only one that really holds up to inspection.

Cross-platform desktop software has been a thing for decades prior to Electron showing up on the scene, there are frameworks designed explicitly to support that, and there is a truly massive ecosystem of native libraries and tools.

I've had experience with crossplatform frameworks like Qt before. It doesn't come close to Typescript, React and CSS in terms of developer productivity.

"Developer productivity" is just the latest tech buzzword. What did devs do 20 years ago and how is there so much good software from back then by today's standards?

You're making the same mistake as people who ask how ancient buildings we're built that they stand so long. You don't see ancient buildings that crumbled down, and you don't remember a LOT of old software that was complete crap. I've used computers since 1995 with DOS 7, and my memories of these times aren't so rosy at all.

This also doesn't consider all the crap software you get today, so you are making the same mistake as well.