> saying she was too busy with courtly life to follow his instructions

That's because his instructions were totally extreme even by today's standards. This says nothing about averages and ultimately as a noble she simply did not want to.

>And exercise, the other thing that's nicer for thinking behind doing nothing besides warm water, was also not really a thing for women then

Are you implying that women just sat around not thinking all the time? Because I am too, but for different reasons, and not just men.

The vast majority of people are not interested in thinking beyond the bare minimum. Otherwise we'd have more than a tiny fraction of the population purposefully self learning.