You seem to be getting different cars mixed up, so what you're saying is factually wrong. Musk never promoted that, and Tesla did complete all of the orders for the original Roadster.

Even if you were correct on the facts, the right thing to do in the face of changing circumstances can of course be to change the plan. In an alternate reality where they had sold preorders for a solar car, making it right to the customers combined with not going out of business is the better plan.