MS has been bleeding market share for a long time. The IE to Edge transition basically fragmented their market, destroyed their brand name, and they never really got back the market share they had gotten used to with Edge. Most people I use that actually use windows, have Chrome or Firefox as their main browser. Apple has the same problem with Safari. I only ever use it to download Firefox or Chrome. Mobile browsers are completely dominated by Chrome and Safari. MS killed their mobile platform and basically serves a niche market for people that really want a MS branded platform there. I actually use Firefox on Android and like it a lot but I'm a minority.

IMHO wasm is approaching the point where it will (finally) create a viable ecosystem for languages other than javascript to be used for mainstream web development. MS, is well positioned with their tool chains to take advantage of that. So, not strange to see MS investing there. Though I do think they need to cut their losses and put their money behind either Chrome or Firefox and retire their in house browsers. Edge at this point is not an easy sell. They did the right thing on mobile killing of windows phone and eliminating that as an internal distraction and I don't see them getting away with having any edge only websites these days.