Windows Phone died because MS didnt do enough to build the app ecosystem, and bailed out too soon. I also feel webOS was a lost opportunity too - in some ways it was just too ambitious for the hardware of its time.
I was one of two non-MSFT I knew of that had one.. and I bought it because an MSFT employee was showing it off and I was convinced. The concept of Tiles was great and Cortana was respectable. It felt comparable to Siri and way better than Google.
I used it for a couple years until the apps I needed started disappearing due to lack of updates.
WebOS needed WASM and a lot more to be successful. I think WASM/WASI is to the point that the next major platform build out can use it.