Here's my perspective with a grad degree in astronautical engineering: Don't count Elon Musk out. He made his millions via Paypal, and his Tesla motor company will revolutionize the electric car industry. So, he has the bucks for the Buck Rogers. SpaceX is already accomplishing engineering feats that will take NASA another decade to complete, i.e. recovering a rocket booster back to its launch point vertically on an at sea platform. His motivation is of course profit, but he also wants to make humanity a multi-planet species. The future of space exploration in the nearby solar system will be driven by commercial space, not government space. The nearest estimate NASA can come up with using the Senate, er, Space Launch System (SLS) is 2030. At the current rate, SpaceX will already have an outpost on Mars by 2025 once NASA finally finishes its architecture studies for its 2030+ effort. The NASA Mars timeline will be fraught with government overhead and process, bureaucratic waste, and needless political manipulation of technology development schedules. I'm glad that Elon Musk is on task so we can finally see footprints on Mars, and a permanent colony as well, in my lifetime.