Elon Musk is not an aerospace engineer or propulsion expert, and while he can talk a convincing game if you examine many of his prior claims you’ll find the bombast to actualization ratio pretty high. That being said, SpaceX has thus far performed beyond reasonable expectations after their first three faltering flights of the Falcon 1, including developing the first domestic large LOx/RP-1 engine since the RS-27/H-1 (but with a high range of throttleability thanks to the TRW-based pintle injector engine), achieving controlled recovery of the first stage through the transonic transition (even though control was lost at low altitiude it was still the most challenging aspect of recovery), and numerous other successful achievements. But this isn’t a carte blanche to accept any given claims uncritically, especially when it comes to cost savings that have been traditionally difficult to realized and are based upon estimates which aren’t validated by information readily available to the public.
I think–and certanly hope–that SpaceX will be successful because even a factor of two decrease in cost will still open up new markets, and the excess capability that the Falcon 9v1.1 has (which significantly exceeds nearly all modern commercial satellites) means that the costs will be shared between multiple payloads and there will be plenty of capacity for ancillary ride alongs (e.g. CubeSats and other secondary payloads) which opens further capabilities for commercial and scientific interests. But as anyone even cursorily familiar with the STS is aware, claims of delivery truck like reliability and turnaround times run into thr hard reality that space launch is nothing like any terrestrial operation, and the tools and practices we use to automate operations on the ground are not matured for use in this application.
Stranger