I would imagine many, if not most, are. Due to the continuing contraction in bus services. Not a recent phenomena either. A larger depot may occur if a number of depots are merged into a single location.
Continuing your theme Crosville / Midland Red / Arriva Crewe moved to the new D & G site near the railway station from the old bus station. First Potteries had a Crewe location which became an outstation at the D & G depot.
PMT / First Potteries had multiple depots. Their current single site at Adderley Green (assuming Crackley out-station did close) may be larger than a single one of those, especially in their latter years, but overall the bus count will be lower.