The patent and trademark office is funded by patents it grants and not patents it rejects. It also has a well documented policy to leave it to the courts to sort out which patents are really valid or not. It's worse than sutpidity, it's policy (the stupidity was the law changing how the PTO was funded, and that is entirely attributable to politicians).
What I would expect in due course? For Tesla to have a few silly patents of its own, and to rather aggressively negotiate a mutual cross-licensing agreement with some other players.That is usually a lot less risky for other players than a trial that may invalidate their patents.