> I can't see how Cocoa failed at anything.

Will my Cocoa app run on Windows, Linux and the web?

(A well-designed web app built with Electron will).

Why should any company that wants their product to be widely available invest in Cocoa developers?

Why should it? It focuses on its platform and does it well.

I prefer native Mac apps to cross-platform ones. Serious companies should build native apps and keep UX guidelines of each platform in mind.

Building an app once for each platform is not economically viable for a lot of teams, 'serious' or otherwise.

Yes, but it's not Cocoa's problem.

It's Cocoa's problem because people stop using it for that reason. A toolkit no-one uses is a failure.

It's doing well - I currently have 2 Electron apps and dozens of Cocoa apps on my Mac. :)

We're talking about dev mindshare today. What you have installed is irrelevant.

I bet that 20-25% of desktop apps on Mac will use Electron in the next 5-7 years.