You have to ask why they required those freestanding boxes, instead of negotiate access to basement utility areas in buildings across the network. Boxes like that may be necessary in less built up areas, but in densely built areas they're a cost-cutting measure.
Maybe it wouldn't be profitable if they had to deal with extortionate landlords, but on the other hand it'd seem likely you'd find a sufficient number of building owners that'd be happy to allow space for cheap or nothing in order to ensure great access.
They need 24-hour immediate access to any box. That means it has to be somewhere accessible. And they can't bury them, because they need ventilation, and the ventilation unit would have to go above ground, and would be even bigger than the utility box was.
Maybe it wouldn't be profitable if they had to deal with extortionate landlords, but on the other hand it'd seem likely you'd find a sufficient number of building owners that'd be happy to allow space for cheap or nothing in order to ensure great access.