I think high premiums for old people is 90% down to old women.
'Most' of the old men seem OK.....but the old ladies will insist on driving their beige Honda Civic through shop front windows, wiping out the girl on the till and half a dozen customers.
The 'old girls' get confused between the go and the stop pedals, you see.
From my experience of having recovered many of these crashes, you're wrong. Old women tend to have a continuing low speed crash, and old men have a more serious single impact. Actually, we don't need the 'old' in that sentence.
I've stated several times here that I don't think old people should swap to automatic cars as they age because you are partially right about the pedals. Although it's not confusion, but terror causing them to freeze in place.
As for insurance companies being ageist, their entire business is based on collecting, analysing and using data. Anyone who thinks their own gut feeling gives them a valid case against that is almost certainly going to be proved wrong. That applies to anything where gut feelings or the even more risible 'common sense' is touted as a valid argument