The real crime is just laziness on the PATH's part. They could run like a 3 train shuttle to/from Harrison to Journal Sq on game days that just went back & forth, to ease crowding, they just don't give a shit. The 4 train isn't super-quick to get to midtown either, but there's always 4-5 of them waiting after Yankees games, so 50,000 people get in & out pretty quickly, even with long lines. (some take the D, but still)
After games, all they have to do is run 3 extra express trains to Wall St. and it would clear most of the lines, and the shuttle between Harrison & Journal Sq. would take care of the rest, along with normal service. Yes, 6 trains sounds like a lot, and you have crews to work them, and it's a union work shift issue, etc, but we're talking about 2 days a month, 15-17 times a year in total. Fuckin' figure it out already.
They can't run express trains cause there's only 1 track each way in the tunnels. Any express train will get stuck behind a regular train making all the stops.