Probably every big city has some kind of street music. I lived in the Chicago area for more than 20 years and heard quite a variety. Off hand, though, I only remember one or two times that I encountered more than two musicians playing at once. I
I’ve only been to New Orleans twice, and don’t particularly recall hearing larger groups there, either, but thanks to YouTube, I have come across some amazing things.
Here’s a group playing “Summertime” by George Gershwin. The video opens and closes with a singer, who is not well recorded. In between, there is an amazing trombone solo. The whole time, another trombonist just sits there with his trombone in his lap. I bet that group could keep playing that one song for a long time and provide plenty of variety for anyone who wanted to stick around and listen for a while.