re: Opening a reception hall/facility?

It's definitely a possibility, I agree many areas lack them and that's what drives the price up. I disagree on the catering, you can certainly make extra money that way but plenty of places just have a small kitchen and have 3rd party caterers. Many have preferred caterers too. Parking is definitely big, gotta have parking for 50-200+ potentially. Don't forget Sunday's, tons of weddings on Sunday's that are Jewish or otherwise overflow due to price savings.

Ordinance is the big thing. It's not easy to find a place to get a commercial permit without obscene commercial prices.

Eta: don't forget about sound. You'll have bands and dj's so you can't be next to homes without pissing people off.