There are companies that exist who target that market. squarespace.com for example.
"Here's your (crummy, last-updated-2011) web site today, and here's the beautiful one we've already built for you, including full online reservations and take out ordering. With just a few clicks you can customize it with photos or a new menu. Pay us $NN/month and we'll immediately switch your domain to point at this shiny new site."
Squarespace could move in this direction, too, by continuing to specialize and extend its templates until a good looking, functional site takes an average of minutes. But Google has the advantage of already knowing enough about the average small business to build it a better web site in literally milliseconds.