I don't know any bank or institutional lender that will extend a loan against a property based on a "nominal value." In every situation I've come across with clients and investment partners, the bank demands to see existing leases in place as part of the appraisal process. If a property is listing space for $40 per square foot and is 80% vacant, then I don't know anyone with half a brain who will accept that $40 as the basis of the appraised value for lending purposes.
I would expect that a prospective buyer or lender would do as you say. But I find "listed prices" for commercial real estate that are clearly based on the highest rental rates charged at the property with no factor for occupancy rates or actual rents collected.
Caveat Emptor, I suppose. Or maybe the current thinking is based on P.T Barnum; "There's a sucker born every minute".
I do notice that those properties do not appear to be selling very quickly. Or at all. But the rents keep going up. And tenants keep leaving without being replaced. Somebody has deep pockets.