Conceptually they all offered a way to write managed-language, write-once desktop applications.

React Native and Electron carry the torch of this style of development now and both seem to be gaining traction in a way their predecessors couldn't. I like both, but can't help thinking that a UI framework designed as a UI framework would have served us better than CSS and the DOM in the long run.

Put simply: Silverlight/WPF and C# could have been a much better Electron and TypeScript if the runtime were implemented in a less myopic way.

About AIR you probably heard hate from people who hated flash. I loved it, (the technology, not Adobe) but also switched plattforms.

Node is a mess compared to it.

Not kidding. I evaluated the capabilities of these platforms and there were some differences but all were better than existing solutions then and now. Flutter on the desktop might be a contender. Can't think of any others.

Yes. Snark.

Then there was the Moonlight knockoff based on Mono. And Mono itself, of course. Dead ends before the project ever started, but they finished and shipped them.

Let's not neglect .Net.

But we're supposed to be talking about good products, not misbegotten ones.

So: Apple Newton!