In fact, Edge launched without support for any kind of plug-in, putting it at an immediate disadvantage to competitors such as Google Chrome, Mozilla Firefox...
Not to worry, Mozilla has heard you and is working on Firefox as we speak.
Hopefully some solution will magically present itself before the Firefocalypse next year when Firefox ESR is bumped up to the borked version. Maybe Seamonkey will get up to speed. Palemoon and Waterfox don't really convince me.