I find it interesting too! For instance, in my family we always host baby and bridal showers at home. I always thought that was the norm until I got to the age where my friends were getting married and all of the showers were a Italian restaurants. My husband family does the Italian restaurant thing too, yum!
All the showers I've heard of were at someone's house, or a rented hall if a large gathering. No restaurants.
A cousin that was married last Nov. had a destination wedding so only had a best man/maid of honor. The couple had a head table that consisted of them in the center flanked by their parents and grandparents.