Because the point of a subsidy is to benefit the public, not particular industries. If others can stand on their own, why would you waste public money on subsidizing a less efficient one?
> The point of government is to serve the public interest. There is a lot of current public-private power generation in the U.S.
Sure, that doesn't go against what I said.
> I also disagree with your assertion that there are renewable technologies that compete with the reliability of Nuclear.
Neither can minicomputers compete with the reliability of mainframes, yet we've seen how that went. Reliability can be worked around with engineering. It'll be a messy mix of power sources, storage technologies and distribution networks, but it'll be cheap. Nuclear will keep existing - at the margins.
I also disagree with your assertion that there are renewable technologies that compete with the reliability of Nuclear.