“Message rejected because text message storage is full” – that has got to be the worst UX on a modern phone

1. why is there a separate “text message storage”?
2. why is it so small?
3. I have more than 20MB of available space in the phone. why not use some of that to back up some of my … 200 (?) text messages?
4. why didn’t you tell me it was getting fulll?
5. how about telling me what I can do to fix this?
6. why is the only option I found to address this one that deletes all messages? who wants that?
7. can I get the text message you rejected now that I’ve made space?