You know, I thought something felt off when I went into a community space today...
I haven't used one for literally AGES - I barely ever leave my lot for anyting. But I wanted to make a farmers market. I set up a bunch of food stalls (over the vendor limit, but the NPCs might randomly pick different ones every time I go so there's variation) but I waited ages and no one showed up.
I have LittleMsSams mod for allowing specific NPCs to spawn depending on what items you've placed (it's a lot trait that allows it) and I asked vendors to spawn that way. However, they seemed to lose the "vendor" designation over the heads and they all just sat on the picnic tables having a chat with each other - still in their aprons. Also felt like a distinct lack of general visiting sims but I wasn't sure.
Obviously, I have mods installed and I haven't tested without so there could be issues. I have the LittleMsSam mod I mentioned and another one by me that tweaks the vendors a tiny bit (allow off lot hiring, $0 cost, and I upped the specified limit of 6 to 50 so it doesn't tell me "you have the max amount of vendors" - It's still a fairly new mod so I haven't had enough play hours to prove that last tweak 100% works as intended. And it seems like I might struggle if there's currently vendor issues!) After a while I tried to hire some vendors myself - I got the notification saying someone would be there soon to staff it but no one came. I left the lot and came back 3 times.
I have closed the game since and I might try again
I am also currently in winter so not sure how the season affects sims coming by - since it's cold and blizzard-y