I think for most people its more about the network effects. Once you switch any iMessage groups you are in get degraded to MMS which means you'll probably just

I think for most people its more about the network effects. Once you switch any iMessage groups you are in get degraded to MMS which means you'll probably just get dropped from the group so that the iPhone users can keep using read receipts/typing indicators, send higher quality media, and get lower latency/higher reliability chat. Even for one-on-one conversations you and the other participant immediately lose a lot of QoL features that you took for granted. Obviously there are crossplatform apps that offer those features but now the friction of switching to Android includes trying to convince every iPhone user you interact with or will interact with to download another app and set up an account or both of you have to deal with a pretty miserable chat experience. Its definitely not the end of the world but if your goal is to promote competition then lowering switching friction has to be a big part of that.