I don't think there's anything they could do to make anyone happy. People who want more than five will complain. People who have one wonder why they need up to five.
You don't know, so why create something so low? I've got 4, I'm sure theres people with 5+, so why not give the ability to have 200? It was a serious question, not a dig. Is there some iOS API restriction on the amount of "pollers" per app you can have some something?