Given that a publically funded manned Mars mission would be at least $10B, a private mission would be difficult even if the cost were reduced 10x. And SpaceX can't even reduce orbital launch costs by 10x over today's gold standard; according to Wikpedia, the Russians have the currently cheapest operational LEO system on a per kilogram basis. Meanwhile, SpaceX's costs are 2x over original estimates. While the Space Shuttle was such a boondoggle that almost anyone could reduce costs as compared to it, contemporary Russian programs are not nearly as poorly designed and executed.
Russian programs are not contemporary: they are early 1970s projects with some 21st century trim jobs. They R&D costs and production lines were amortized before Reagan came to power.
That doesn't make it any less contemporary or cheap. They are operating today, and they cost less. If your goal is to get mass to orbit for the least amount of cash, that's all that matters.
There's also the march of technology to consider. 1970's technology isn't going to be cost competitive forever, even with amortized R&D costs. When SpaceX gets to the point of delivering complete reusability, there's going to be a shakeup.
