If Musk guts NASA, then surely it would be in an attempt to benefit SpaceX and himself, e.g. by removing regulations or funneling more money to SpaceX, and with that accelerating his Moon landing program, not pushing it back.
I didn't say anything about Mars, I only meant the Moon mission, which I assume would slightly push the record further just because the longer duration would give more opportunity for the wobble of the Moon's orbit to get the astronauts further than before.
Granted, SpaceX could also just fail to get to the Moon.
Considering his successes with Tesla I doubt it would get the desired results. But spacex does have some very smart cookies, so you might be on to something.