Never claimed it was Apple’s responsibility. They could have helped building the next gen but instead walked away.It isn't Apple's responsibility to make SMS/MMS E2EE (end 2 end encrypted). SMS is the fallback for messages. There is a case that could be made that a default fallback should be available to all Messaging Apps that allows them to interoperate but I do not know if that fallback should be SMS.
If you want secure messaging with Android you cannot use the messages app, that is not Apple's fault nor is it their responsibility to fix this.
It isn’t “secure messaging with Android”, rather messaging with non-iOS parties.