Also, imagine this scenario from the perspective of a non-technical user: You buy an expensive but high quality phone that's easy to use and has a great camera and great apps. Most of your friends have the same phone and everything works great with them. Then you try to talk to someone new but they have a phone that was probably cheaper and has a worse camera and looks like it's harder to use and full of ads. Every time they message you it turns off a bunch of your features and ruins group chats for everyone. Who are you going to blame, your phone manufacturer whose product seems to work great, or this guy with a phone so cheap and buggy that it breaks everyone else's?
Thus, non-technical iMessage users see no reason to go out of their way to use weird third party messengers. It's not their fault - it's the android users' faults for being cheap.
(For clarity, I am a hardcore android phone but I'm not delusional enough to think the average person will have a better experience on Android then iOS. I had to install fdroid and a custom launcher and a bunch of side loaded apps to get a decent experience. The average person doesn't and arguably shouldn't need to know about all that)