I agree. I think a lot of people do this already, and not just for sites where they can't remember the exact URL. It's often just as quick to type 'bbc' or 'facebook' into the Google search bar, especially if Google is your homepage. You don't have to worry about typos, either. Some computer users I know, older users, access everything that way. When I asked one why, she replied that she found the browser address bar "fiddly".
Earlier this year Bing stated that "about 30%" of search queries are navigational.[1]
If anything, so many tlds would devalue the existing .coms, .net, .org... if only slightly.