Indeed, if the politicians limited their involvement to defining an energy market which would provide stable supply plus a margin for growth the utilities themselves could focus on the specific technical aspects of providing cheap power. Subsidies for specific technologies are simply a waste of money and can actually inhibit better solutions to the problem when it doesn't come from the source you thought was the obvious answer.

It's a bit like gardening. Sometimes the weeds aren't weeds.

We are seeing it with the massive rail subsidies which exist across europe as well. Technically superior replacement systems are inhibited by the government support for the incumbent systems.

Still, I don't expect people to learn from their mistakes.

What gets politicians deeply involved in nuclear technology selection is that same old problem: the tendency of private enterprise to socialize the risk, privatize the profit.
The risk in a wind turbine technology is quite low so you don't see any wind energy companies going to government for liability protection. The nuclear industry, however, has got risk protection from the US congress explicitly and in the EU it is there at least implicitly as the EU governments realize they will have to fix whatever screws up.
So ultimately, the politicians know they will have to fix any screw ups and that gives them a deep and abiding interest in all facets of the industry, including technology selection.