I wouldn’t assume supply is the main explanation yet. Buyer financing and seller motivation can create the same quick-versus-stale split, especially within a relatively narrow price bracket.
I’d make a small table for each listing: exact neighbourhood, first appearance, withdrawals or...
I partly disagree that the warehouse necessarily brings more control: access, shared yards or building-wide arrangements may still constrain it. Before choosing, request the last few years of costs for both, details of any planned shared works, maintenance responsibilities, current occupancy...
Hagastaden and Hammarby Sjöstad would not be interchangeable just because both searches contain newer flats. Even within one area, proximity to construction, transport or water can make a broad neighbourhood comparison misleading. Keep the radius tight.