Which browser engine are you getting on iOS when you install Firefox?
If you answered Firefox, you are WRONG.
You get Safari, because Apple forces all browsers on iOS to use their own crippled browser engine.
Apple also is part of the W3C board that gets to decide which APIs get to become standards, so they also influence what other browser makers do.
This would be a non-issue if Apple didn't force all browsers on iOS to use their Safari engine.
No, you get Firefox.
There is much more to a web browser than just its rendering engine. When you install Firefox on iOS, you get Firefox. It uses the WebKit rendering engine, but it’s still the Firefox browser.
To be frank, it’s pretty insulting and dismissive to all the people putting huge amounts of work into building browsers only to for you go around telling people that all their work is really just a mirage.