Basic probability theory has been useful to know since there was any basic probability theory to teach, so this seems like an odd case to choose for making a point about technological change. The reason why it isn't reliably taught must lie elsewhere.

Correspondingly, mental arithmetic is hardly an obsolete skill. Just because we use Excel or Python or a Casio calculator to do 99.9% of the heavy lifting doesn't mean it isn't essential to be able to confidently manipulate quantities in our heads.

I don't know about the U.K. but in Germany probability theory, even at the senior level, hardly consisted of more than combinatorics, which is probably the worst way to teach probability. Only nowadays curricula are slowly catching up.