Yes, everyone knows this but you're not supposed to mention it. If you have green bubbles, you risk being a social pariah. Android use among teenagers, who are most susceptible to peer pressure, is >80%. Also I know several guys who switched to iPhones and suddenly had a much better sex life. It is what it is. Think of Apple buy-in like a tribal tattoo or rite of passage for young people.
If Apple released iMessage for Android or made it compatible with another protocol like RCS/WhatsApp/Signal/etc., then Apple would lose half of its market cap. I'm not exaggerating.
You know iMessage will always be there - at least as long as iPhones are anyway. You also know there's no third party snooping - not the case with other messaging systems. Also there's no cookies or location tracing (like I imaging there are with Facebook messenger etc). Thats how I feel about it - rightly or wrongly, its as reliable and secure as the SMS system, but without the spam.
If Apple released iMessage for Android or made it compatible with another protocol like RCS/WhatsApp/Signal/etc., then Apple would lose half of its market cap. I'm not exaggerating.