It seems to me that a lot of our supporters don't learn. 10 out of the last 15 domestic trophies won and cup defeats this season in an FAC semi and the UCL final (our only defeat in that competition) shows that Pep learns plenty.
Also, what people miss is that Pep did need to make changes for the Chelsea game; hard to deny that he got them wrong but also hard to deny that whatever he had done, the player might well have failed on the day.
However, the tinkering if that is how you want to describe it is what leads to Pep continually improving the team and learning about them and the game.
He will almost certainly tinker next time we play Chelsea and the chances of him getting it right will have improved.