First of all, the high-voltage filter capacitors have a certain size and in most cases even a low-capacitance/high voltage filter caps are quite large. It will probably require much larger space to mount 10 100uf/300V caps than to mount 2 x 500uf/300V + the price of first ones is technically much higher than in second case.
Higher collector voltage for SS or higher plate B+ voltage for tube amps dictates higher capacitance for filtering larger pulses and certainly higher energy storage to supply the output stage during peaks.
Higher collector voltage for SS or higher plate B+ voltage for tube amps dictates higher capacitance for filtering larger pulses and certainly higher energy storage to supply the output stage during peaks.