Nobody's proposing "just a few years". Both Musk and Bezos have grand visions that require difficult, complex technical and financial problems to be solved.

First up is lowering the cost of escape velocity such that "casual" flights are financially feasible. This includes reusable components, a very low failure rate, and an ecosystem of employees, engineers, and culture that supports it.

If M/B achieves their stated goals in this domain, then the next steps can be practically executed.