You could argue that it already did become incredibly widespread (as php) then died off slowly due to market forces.

I wouldn’t say Hack was ever popular as a language. The HHVM certainly had popularity as a runtime for PHP until the speed increase of PHP7.

I seriously can't remember any (incredibly) widespread use of Silverlight – could you elaborate? The only instance I noticed it was with a video streaming platform.

Biggest use of it that I'm aware of was Netflix. This was really just done for DRM reasons.

I don't think Silverlight had a mass amount of public use (Flash and Applets were still available at the time - so there was no pressing need).

But MS really did earn a lot of bad will from their dev community who had been pushed to learn yet another framework which ended up dead.

I rarely even use my PC anymore. I basically then it on once a month to download the gigs of updates. It's interesting that Silverlight still listed at the top of optional updates.

There must be a few businesses and schools who bought into the hype and built their internal app on SL.

My previous employer sells a legal review & production solution with a Silverlight UI. I left half a year ago, but if all is well they have just finished reimplementing it in Angular.

The management console of the AV software we use at work is built in Silverlight, but that is about the only instance of Silverlight I have ever seen.

Silverlight is used simply because MSFT grant the use of their DRM license, unlike Adobe at the time.