It's not really tech startups I'm worried about as they are more likely to receive VC/angel and can be started by young hackers. I'm talking about your average small business, whether it be a self-employed consultant, a small hardware shop, a bakery, mechanic shop, cafe, etc. I observe that small business has been decimated in America and giant chains have proliferated. When you drive through small towns in the US you will usually find a few large chains like WalMart, McDonalds, Jiffy Lube, etc on the Main St and not much else. When I travel UK, Australia, NZ, Europe, small business seems to be in better shape. Much of this is due to active skepticism of large corporate chains and their scale advantages (trading hour restrictions come to mind).
I think there may be some confirmation bias there; the UK is also discussing the question of what it calls "clone towns", where all the high street shops are either national chains, charity shops, or empty unlet units. The big ones like ASDA/Walmart are out of town.
I think the only place small businesses are really thriving in Europe is Germany.
It depends on the town a bit I think. In Brighton there are lots of small business and some areas have no chains at all. Not sure if that is because of planning policy or for another reason.
That's very definitely the result of both council and cultural factors. Brighton is special.
Mind you, so are a lot of other places. I see from http://www.rudi.net/node/22184 that Cambridge is very clone-ridden, which feels about right. It's an odd collision between architecturally interesting colleges and medieval street layout on the one hand, but an almost total lack of properly local shops due to high costs. Since the takeover of Heffers and Eaden Lilley the only one I can think of is Mackay's.
