It isn't about you, it's about me who can't install iMessage on an Andorid phone or a Linux desktop and participate in your group chats in reasonable capacity.
I postulate people would gladly pay a cup of coffee's worth for a first party app and/or subscription. Certainly easier than shelling out a few hundred bucks for an iDevice.
That’s kind of what I think. Make an iCloud subscription tier that includes access to messages and then include it in the web-browser version of iCloud and make an Android app for messages. I can’t imagine it would have to cost much more than $10-$15.
This would be an Apple service. It'd cost $99/month to view the text of messages on non-iPhone devices, and an additional $99/month to view any photos/videos/emojis attached to messages.