At the rate FB is going, I can see an uptick in people not willing to install messenger, etc. either moving away from social apps or finding other alternatives. For me, if they force the change on iOS, I will definitely be cutting back.
Honestly, most people don't care. The only reason my SO doesn't use the Facebook app is because it kills her battery too much to be able to use Instagram later on in the day...
As of today, I can't read messages on m.facebook.com any longer - instant redirect to play store/messenger, no way to access messages after going back.
