As an Apple customer here's my thoughts on this:

1. Yes I would love if iMessage went Android and all my Android friends were able to react, thread convos, and all the other perks that iMessage allows, BUT the color of the message doesn't matter to me. I'm ok with the green bubbles too.

2. If iMessages was available on Android, I and every iPhone user I know wouldn't be like "finally, I can leave Apple!" iMessage is a perk not the main draw. The wider ecosystem and walled garden that non-Apple users apparently hate so much is not-surprisingly lovely to those of us all in on it.