All aspects of Community Spaces and other Community Lots have been nerfed since a recent update.
Community Spaces....
As said in OP, with Marketplaces the vendor tables cannot be stocked and no other Sims use them although lots of Sims turn up and chat. The Vendor van is there but cannot be activated.
The default community space now has no one turning up at all, not even to look at Community Board and vote or interact with dumpster and Guntdach recycler which they used to do.
Maker Spaces have about four Mentors turning up, Recycling Guru, Maker Mentors etc but other than them the only people who will enter area are your controlled Sims or their traveling companions. If one of those mentors is Tina, she will use items, eg Fabricator, but no one else does.
Community Gardens. No one turns up.
Other lot types eg Recreation centers, Parks, Art Gallery, etc
Autonomous actions seem limited to items that appear in that lot types required items list or Community Items list. Because vendor vans only appear in two, they are the only ones where they can be hired. None open automatically anymore
Similarly woodworking tables get used if listed as a required item, but not if just placed there.
Previously you could add all sorts of items to a basic park and it would be used and interacted with by non controlled Sims eg dumpsters, recyclers, fabricators, wood working tables, candle makers, easels, gym equipment, garden beds, mitey mitey houses, vendor tables. Now nothing gets used except for standard park items, eg chess board, grill.
This has been proven by changing lot types, and placing "required items".
So please either remove this strict adherence to items or add more items that can be used.
There is a discussion and screenshots in this thread: https://forums.ea.com/idea/the-sims-4-bug-reports-en/eco-hardly-any-sims-visiting-community-space/4996657
I've since discovered with Market Places if you take your own table, you can Place it in World and man it yourself. The Sims who had previously just been milling around, come and look at stock and sometimes buy. No one tends the provided tables.
