That seems a bit condescending to restaurant owners? Rather, perhaps, they are so much in the real world, dealing with suppliers, cooks, kitchen equipment, waiters, decor, etc., that navigating the virtual (websites) is antithetical?
I didn't say they are too dumb to figure it out... I just said they are barely figuring it out, probably because of all the things you listed.
But I do really love the idea that there's a dialectic between the virtual world of websites/internet and restaurant work -- which is so deeply grounded in the physical. And that there's some meaning here, that these things do not reconcile well, and the lameness of the web presence of restaurants is a living manifestation of this disjunction.