Earlier quoted context omitted.
Note that the BBC is funded primarily by what's known as a "TV License"[0] in the UK - I think it's entirely possible they could probably increase ads or something for international viewers but understand why it isn't their area of focus [0] https://www.bbc.com/aboutthebbc/governance/licencefee
I believe the bbc provides its shows internationally via other channels, for e.g. https://www.bbcselect.com/watch/take-me-to-titanic/
https://en.wikipedia.org/wiki/BBC_Select_(streaming_service)