LOLSMS isn’t end to-end encrypted on any phone, rendering everything you just said moot.
Someone didn’t think this all the way through, that’s true. Just not who you think it was.
Of course SMS isn't end to end encrypted. That's why Apple left it in second citizen class and gave it the green bubbles.
All of Apple's actions over the past several years indicate that they want to encrypt all communication.
The SMS is the legacy that needs to be supported.
Why would they start supporting new unencrypted technology when the company's strategy is to head in the opposite direction?