They didn’t used to be. You really had to pound them long term before they would mess up, or if they leaked and never got replenished. I used to work in a trans shop in the late 90’s and we just didn’t see many Chryslers or Hondas. But at some point, both companies dropped the ball. The Chryslers we saw inevitably had this POS known as the 604, a 4 speed front wheel drive auto.
For Chrysler and Honda – They used to be reliable but shifted kind of weird. Owners complained, so they smoothed things out. “Easing” into gear creates heat and friction.
So, the smoother it shifts, the more it is tearing itself apart. Seems counter-intuitive. Maybe compare it to setting a heavy object down quickly as opposed to slow and gently. Which one is going to take more work?
The problem with modern transmissions is there is too much crap going on inside. Add that to the fact that there is some electronics involved (another possible failure) and It is not a question of “if” but “when” they will fail. The more events taking place, the more likely a screw-up will surface.
Just imagine the mess in a couple years when these 9 speed automatics start screwing up. Oh it is going to be BAD.
The problem with trans screw-ups is they are the hardest thing to get to, remove, and rebuild.