Holy moley, you edited your post and made it worse. Apple is not forcing you to be in their ecosystem... you are, as you told your teens you had no problem if they got iPhones (or got them for them), but obviously have a problem with that. I keep reading comments in these Beeper threads from parents about peer pressure on teens in the US to own iPhones and all I can think is why are parents teaching their children to put up with peer pressure. One person was running a Blue Bubbles server so his kids wouldn't be bullied for having Android. What the heck is wrong with parents that they are giving their children the message that faking that you have something is the correct behaviour so you can hang out in a chat with people that bully other people. Good lord, that is so many wrong messages to send at once.
I have Android devices and make no apology for it, because anyone that has an issue with it is the problem as far as I'm concerned, not the device itself. I also have iOS devices, but I'm not an Apple fanatic and Apple does lots of things I do not like. Having their own messaging protocol that was better than the methods that were current at its time of introduction is not one of those things, and a company spoofing an Apple device to use that protocol is another example of behaviour that I find annoying, especially when that company tries to the pitch their service as "for the common good" while charging customers to use it to piggyback on Apple's servers. That is a mighty strange "high road" to try to take. It is just annoying to read people complain like they are owed something by Apple beyond the device and service they were sold.
That said, I'm happy Apple is adding RCS and expect E2EE will be included in the final implementation, but I'm sure some people will still complain, even then.