I think you are missing the point - quite a bit. No one is asking Apple to give up iMessage and replace it with RCS. The ask is to replace SMS fallback with RCS fallback. When you message someone without an iPhone, you currently use SMS. Even though you are using the iMessage app, the message is sent using SMS.

With RCS instead of SMS, iMessage will continue to "Just Work" as it does right now. iOS<->iOS will still happen over iMessage.

> I had an Android phone when RCS was rolling out. It never worked.

It has rolled out now though. No one asked iMessage to support RCS back then. They are being asked now. So it's not relevant what happened with you whenever you had Android phone.

> Well before then, iMessage - like most message platforms - already did everything that RCS did and far better.

iMessage did that for iOS<->iOS communication. Not for messages sent over SMS.

> No other messaging app is as simple and easy to use as iMessages.

This won't change with RCS.

> I will never trust a google messaging service to last and be around in 5 years.

The protocol should stay there as the SMS one is still around. If G gives up support, the fallback for RCS is... SMS which is anyway supported by iMessage already.

Disc: Googler but nowhere close to Android, RCS, any messaging app.