Wenger has never been a tactician, but the crap about him not being a motivator and not being good in the transfer market is crap.
Wenger didnt lose his mind though. He just got old and out of touch. His tactical failings shine greater now since Pochittino and Guardiola are in the league now. Even Klopp's basic tactical self is better at it than Wenger. Mourinho is having similar problems with United because the game isnt won on the transitions anymore like his early Chelsea sides used to stunt.