I work at a Super and we literally have 1 food assistant (which I'm assuming is our equivalent to PA) even though we have 1 TL each for Grocery, Bakery, Produce, and Deli. They've decided to eliminate the food assistant positions and our one was simply grandfathered in. Now there's no stepping stone in the food areas between TM and TL... which means we have TLs who either have no help leading their team or they're forcing a "favorite" TM to take on more responsibility than they're being paid for. (That's how I see it, anyway... and it has already led to TMs resenting other TMs because they're being "bossed around" by someone on the same level as them.)
Edit: From what I've gathered reading here for some time, though, is that 1 or 2 PAs is pretty normal... and 100% unreasonable for many stores.