it is impossible to literally use all 4 catapults simultaneously without the aircraft hitting each other. At best 4 catapults all saw staggered use within a certain period of time. If the 4 catapults are all in working order, then all 4 could certainly be arranged to all see staggered use within a long enough period of time. The crux of the question is over a given period of time, can using all 4 catapults in a staggered manner get more aircraft into the air than just using three In a staggered manner.
if not, then the claim that all 4 catapults are used simultaneously is misleading for the purpose of the discussion here. yes, all 4 catapults are in use, but the usage is more accurately described as rotating rather than simultaneous.
also, keep in mind during the 1960s and 1970s, a good percentage of planes on US carrier decks are the relatively tiny A4s, which , if I am not mistaken, is much smaller and lighter than any catapult aircraft currently I. Service anywhere in the world. So the steam use associated with launching A4s might be much less than launching any aircraft today. So even if available steam allows catapults to cycle fast enough with A4s, such that using 4 catapults together really can get more planes into the air faster than using 3 together, that does not mean the same remains true with heavier modern catapult aircrafts.
