FWIW Alamo is really strict against talking. I've never had an issue, and they have staff walking around enforcing (they're already walking around for orders anyway).
Even if people weren't talking to each other, there's a lot of low volume conversations happening with the waiters and people use their phone to illuminate menus and to see what they are eating.
See an angry voice mail from one customer https://www.youtube.com/watch?v=1L3eeC2lJZs, or the playlist with a long list of PSAs, many of which include celebrities, asking you to please not talk: https://www.youtube.com/playlist?list=PLpX5OvrhWl9I59CYEx_Zt...
Props to anyone who can get Neil Gaiman to make a please no talking PSA in the form of an Agnes Nutter prophecy.