Are you talking about the pumps, Frac tanks and other equipment that get moved to each well site? There isn’t an infrastructure like gathering lines or other permanently installed equipment.
Those are used after drilling is completed and before the well goes into service. Occasionally they are brought back to an existing well in an attempt to bump the flow rate back up. The well is not producing while that is being done.
If pumps, tanks and other equipment are just left to rust for years with no maintenance, there will be problems when brought back to use. But most Hydro-Frac is done by major companies like Weatherford, Schlumberger, Halliburton and Baker Hughes. They are not going out of business; they will maintain their equipment. They know this won’t last forever. Also, they are still get some hydro-frac work, just less than before.