It's interesting to see how cities are handling the increasing bifurcation of wholesale and retail markets.
In Sydney, the current Fish Market is a grotty assemblage of small warehouses in what's now a prime waterfront location of the city that has become an unlikely tourist attraction, but still serves the wholesale market. They're building a new one right next to it that looks far nicer, leaves tourists much less at risk of getting impaled by a speeding forklift, and will keep the wholesalers around for at least some time since they've been promised fixed rents for the next X years: https://newsydneyfishmarket.insw.com/insw/new-sydney-fish-ma...
All other markets, though, have been shipped off to a massive complex in the industrial suburbs, designed for wholesalers with easy truck access, and with the arguable exception of Paddy's Markets (which mostly sells junk to tourists) there's not a single proper consumer retail market in the entire city. Meanwhile, over in Melbourne, there's a whole slew of them (Queen Vic, Prahran, Footscray etc) that all appear to be thriving.
Yes, although it sounds like Preston has / is / will be at risk from developers that own the land and want to build apartments.
The thing about markets like this is that once they're gone, you can never get them back again. My home town, Wellington, shut down the markets at some point in the distant past and have been trying to restart them in the more recent past to little success (think a bunch of cars parked in an uncovered car park trying to sell vegetables).
Indeed. The central Sydney locality of Haymarket is that in name only. Same for Wheat Road and The Goods Line. Wholesale fresh produce has all been in Homebush / Flemington for years now, barely accessible to anyone without a semi-trailer and the willingness to purchase a truckload. Shipping also long gone from the central spots of Walsh Bay / Barangaroo / Darling Harbour, all now relegated to Container City aka Port Botany.