I think he's envisioning this as a one-way trip: $500k for a house in California OR settle down on Mars. In that case, it's actually an affordable price tag. Even if EM realizes his reusable rockets, I imagine the primary purpose would be for transporting supplies, etc. rather than frequently shuttling people Earth <---> Mars.

Just think of immigrants from the early 1900's who uprooted their entire families and got on a boat to America. That was a one-way journey in most cases until international travel became more affordable and more commonplace. Interplanetary travel, when it happens, will likely take the same pattern.