This notion that nationalization of industries being antithetical to competition only applied when you're talking about the insular economies of the former Soviet bloc.
The chaebols of South Korea are essentially nationalized companies, but they compete very well on an international level.
Just as we talk about how unhealthy it is for infighting between WinDiv and DevDiv within Microsoft, it would be equally unhealthy for there to be "infighting" between Microsoft and Apple, if US technology companies had to compete individually, without government backing, against nationalized companies like Samsung as well as huge nationalized technology companies that may someday arise from China, India, etc.
I've spoken out against companies becoming "too-big-to-fail", and have argued for regulations preventing this, but that's only from the context of these companies being private companies that needn't answer to the government yet reap the benefit of the safety net that the government is willing to offer. I would be all for allowing "too-big-to-fail" companies to exist as long as they are nationalized. Hey, I like lower taxes too. So if some guy from the Netherlands buys a product from a US company that benefits from the "too-big-to-fail" safety net, then I expect the profits to go directly toward lowering MY taxes.