As a web developer, this is not true. An large number of clients I've worked with have used IE and thanks to Win 10 shipping with Edge (which in itself is a decent browser) I've noticed a huge decline in "but it looks odd in my browser" comments from clients. So while I don't like Windows, or Microsoft in general, I do like the push to get rid of legacy stuff by them.

What I have read so far is that Edge usage on the web is marginal despite (forced?) windows 10 adoption.

Yes it is, but lots of companies have upgraded to 10. Of all the offices I visit I see Edge open a lot. Chrome of course is the most popular, but I'm happy the awful web rendering engine that is IE is soon gone.

One time I used Edge for about two months on my Windows PC just because I was too lazy to download and set-up Chrome after format.

The only reason why eventually I switched to Chrome was Chromecast. Other than that Edge + uBlock Origin was doing everything any modern browsers do.