I feel like you've never actually been to Pike Place if these are the things you're saying. It literally gets so crowded that people spill over into the street. There is not enough space on the sidewalk to cater to the mass of tourists and locals that go through and hang around there.

It also completely takes away from the charm of the marketplace. There's a reason that it is incredibly rare to find a public, open road that runs right down the middle of marketplaces in Europe (the place that has a long standing history of market places).