I don't think you understand space and space technology well enough to evaluate SpaceX if you think there's no way to 'generate' gravity in space without using space magic gravity generation.
We've currently never built a manned space ship for month long travels in outer space. We've never built a space ship that uses centrifugal force to simulate gravity and done longitudinal studies to verify that this doesn't have an adverse impact on Humans. SpaceX is has a market capitalization of 33.3 Billion. SpaceX which was founded 17 years ago has never had a manned flight. SpaceX has also never had a flight leave the atmosphere so far. But yes, it's entirely believable that they will go to Mars in our lifetime.