It's both. A whole bunch of this stuff is old. That which is not necessarily old doesn't have the spare parts to make sure that it can run adequately, especially when you use it for advanced training, where vehicles tend to get beaten up a bit.
What is needed in this particular instance is a threefold increase. One is for additional mechanics and for people who can service those vehicles. The second is for the ammunition to actually allow the systems to train, and for the gas and the spare parts. The third is the people to actually man the equipment, because with more people, you reduce the individual stresses and workloads, which have contributed to a higher attrition rate.