According to netmarketshare[0], on desktop[1], Edge currently has 3.8% market share, more than Safari and Opera together. Combining mobile+desktop Edge has 2%.
Edge cannot be ignored if one is serious about any kind of business: that's 3-4 out of every 100 desktop users (existing or potential customers), or 'just' 2/100 if one includes mobile.
— Honestly, it seems that you are trolling. But I post the above stats in case you are not. But I also back it up with my own personal 'anecdata': I build business-to-business ecommerce, in our specific market our users are primarily (>95%) using desktop browsers, we have many thousands of existing business relationships, we cannot mandate which browsers they use — we draw the line at having the site simply work in all "modern browsers", which obviously includes Edge.
It doesn't really matter whether it's "many browsers" that don't support Web Components, or whether it's just one major browser. For many businesses, choosing WC is simply not a viable option for the foreseeable future.
You are reading it wrong, it is not me that mandates the browsers.
I have written already in multiple answers, it is the customers that decide which browsers should a given project support, by explicitly stating them on the project delivery contract.
So your customers care about EDGE, fine. Many don't.
Mobile web is all about Safari and Chrome.
Again you keep avoiding to explain what "many browsers" means.