You hit me right in the gut, are we long lost siblings? Lol
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.
I loved Google+ - it was like Facebook without the dark patterns. So of course, nobody was on it (which I didn't dislike exactly).