Brunel was probably right that the work of the commission would be detrimental to the rate of innovation. But is that the only thing that matters? We would probably get a faster rate of innovation in personal transportation if we allowed any unlicensed vehicles to use the public highways at any speed. But there would be a terrible cost to pay in terms of lives lost or ruined. It doesn't sound like the commission was planning to forbid any and all usage of cast iron, just not in places where public safety was at risk. An innovative engineer could always build a novel cast iron bridge in a test location and produce some dramatic demonstration of its strength and reliability that didn't involve running fully loaded passenger trains over it. The trade-off between the rate of innovation and the casualty rate does not need to be chosen at either of the extremes.