[inimino]

Is it rational for a customer to not fly on a plane that is as safe as any other just because the same company later made another plane that was less safe? It seems like a lot to ask.

In any case, even if 10% of people totally stopped flying on Boeing, which would be a wildly optimistic outcome for any organized consumer action, the airlines would just discount those flights ever so slightly and the other 90% of price-conscious consumers would immediately take up the slack. Nobody's going out of business in that scenario. This is, of course, why we rely on regulation rather than consumer choice to ensure safety, and why this is a failure of regulation, not of the market.