Texts not received on iphone 14

I have a limited data contract on my iphone 14 and find that I do not receive some messages when out of wifi range.

I think it is because of imessage.

I have got the ‘send as sms’ turned on.

I am guessing the people trying to reach me don’t, but can’t be sure about that.

I am amazed that Apple chooses to block these messages; surely the default on a phone should be ‘try by imessage and if that fails use sms’ without requiring people to change things in Settings?