Between avoiding "bottoming shocks" (if you can't stay off an RN ship, don't fall for the "golden rivet" line) and "it was leg closure that was the issue" this thread seems to be under the influence of Round the Horne scriptwriters...
Back to topic. Ski jump is physically simple but you can get hung up in the idea of "where does the force to move the aircraft up come from?" when in fact what you have done is changed the vector (presumably, though, the jet would be moving a little faster coming off the end of a flat deck, given the same distance, weight and thrust).
And Engines is right: the USMC does mass trooplift and giving up deck space is taboo.