Not even young at this point. I overheard two grown men talking about how much they hate people with green bubbles and purposely skip inviting them into group chats because of it.
It's less about the background color and more about the endless series of interoperability paper cuts that exist with green bubbles. Will my reaction emoji come through as intended? Will my shared media get downsampled to feature phone quality? Will referencing the person's name in chat work the same? etc etc etc.
Interop is always a pain, but the sooner Apple can be forced into making any concessions the better.
It would help if Google wasn't a complete joke in the messaging space though. As much as I want iMessage interop with Android users, I have no faith or trust in any Google-based messaging app or initiative. Fool me once, shame on you; fool me dozens of times ... well I'd be an idiot to trust Google messaging again.
The fact that a huge number of perfectly good third party chat apps exist and yet most Apple users prefer iMessage is a huge testament to iMessage just being a really well made product. I wouldn't put up with the obnoxious interop and lockin issues if it weren't!
Recently Google Messages started automatically translating the shitty little 'So-and-so hearted "<previous message>"' SMS messages Apple sends out from iMessage into reactions as well.
It's genuinely quite good. I prefer it over Signal when I know the other person has an Android too.