Let's be clear. Green vs blue is a bit of a red herring.
The real issue is that Apple has to have some fallback protocol for texting with non-iMessage devices, but refusing to upgrade the fallback protocol beyond SMS/MMS makes the texting experience worse for everyone, as described in the article.
(To avoid additional red herrings. No one is thinking here about opening up iMessage itself to non-Apple clients, just upgrading the fallback option. Also, I can't speak for everyone, but among the non-terminally-online Gen Xer and late-Millennial Americans I know, "texting" means using the built-in app on your phone. Switching to another app is a relationship step. Many of them are blithely unaware that they can't "just" text a photo or video to me or other Android users, nor that I can't just sign out of a group chat when I feel like it.)
SMS is also the fallback protocol for iMessage. If I’m in a place with poor signal, even my texts from the Messages app on my iPhone to my spouse’s iPhone go as SMS.
Edit to add: those bubbles are green too. That’s what the bubble colors really mean. Blue and green are not iPhone vs Android, it’s iMessage (end to end encrypted) vs SMS (less secure, less private).
The real issue is that Apple has to have some fallback protocol for texting with non-iMessage devices, but refusing to upgrade the fallback protocol beyond SMS/MMS makes the texting experience worse for everyone, as described in the article.
(To avoid additional red herrings. No one is thinking here about opening up iMessage itself to non-Apple clients, just upgrading the fallback option. Also, I can't speak for everyone, but among the non-terminally-online Gen Xer and late-Millennial Americans I know, "texting" means using the built-in app on your phone. Switching to another app is a relationship step. Many of them are blithely unaware that they can't "just" text a photo or video to me or other Android users, nor that I can't just sign out of a group chat when I feel like it.)