Why Must the Bridge be Half Full?

It’s simply not done in the US. Bridges in US towns aren’t full of people selling things. I assume that this has more to do with the US’s rather single-purpose approach to bridges, as opposed to the historical aspect of bridges in Europe that were often the focal point and reason for being of a great many towns. For example, Mostar owes not only its existence to the bridge in the center of town, but also its name, ‘most’ meaning ‘bridge’ in Slavic languages. Then of course there is London which came in to being because it was the widest spot down the Thames where the Romans could span a bridge.
I bring up this history because it’s the only reason I can find for filling bridges with all kinds of things to buy. The Charles Bridge in Prague is one of the more egregious offenders I’ve seen lately with the bridge only open to pedestrian traffic which gets to meander through countless bouts of touristic ephemera to reach one side or the other. But while in Budapest, I saw the same thing on the Chain Bridge. The one big difference being that the goods for sale didn’t have that tacky tourist element to them that I saw in Prague. They seemed to be more handmade products of the local vicinity. The reason that it is apparently a bit better in Budapest is the fact that the bridge is only closed on Sunday to traffic and only during the summer. The intermittent closures seem to stem the tide of tourist wares from washing up along the sides of this particular bridge.
So, while I find these examples less than fantastic, I refer back to the history of bridges in Europe again and when looking at a bridge like the Rialto Bridge in Venice, you see that having small stores on a bridge is actually quite historical, so it seems it would be only natural for this to continue. From an American standpoint, this is hard to get used to. Our bridges are just for spanning something, not for selling something upon. But this is all tied in to the fact that for the most part we lack town centers. So, naturally, even if an American town grew up around a wide spot in the river where a bridge was built, the bridge was never a focal and thusly, commercial point. The town just kept spreading in the way that only our towns could. In the end, I suppose it comes down to the perception of things and while it would be nice to have more normal, authentic things being sold on bridges in Europe, there is a rhyme and a reason for things being sold on them in the first place.
Why Must the Bridge be Half Full?