In my experience most of the party places allow you to bring your own food/drinks (with some limitations that they specify in the contract) but often have "a recommended pizza/snacks delivery" that you usually just add on to your whole package.
Our last party's place specified that you had to order pizza through them but we were allowed to bring our own drinks/cake/cold items (they specified that no other hot food besides their "approved" pizza were allowed).
Since the party place was close to Wegmans and since I was already getting drinks/cake from them I decided to get some party trays from their Catering Department. BEST DECISION EVER. Kids devoured the "kids finger sandwiches" (very tasty, cute and adorable) and adults loved their "adult" wraps and sandwiches. Also some sushi and fruit.
This was my first experience with Wegmans catering and they were extremely professional through the entire process (and in now way I'm connected with the chain just thought it by far exceeded any expectations re "grocery store catering").
I probably spent about the same I would have spent on pizzas but after the party almost every adult came up to me and asked where did I get the food and told me how much they enjoyed the break from usual birthday party pizza routine.
Just throwing it out there (and I would not mind if it would start a trend

)