I might be wrong, but I think the landlord is offering the downstairs neighbors an apartment in a different building.

Unusually, he didn't put the music on today. I heard someone (who sounded like him) getting out of a car at lunch time say, "It's a studio!" With disappointment. The unit he has here is a one bedroom.

I'm not certain about this, but I think this is what's happening. I would still be left with the stamper upstairs, I guess, but maybe without the group involvement she would stop stamping.