Yes, if China had subsidized the US installation of massive new electrical power generation capacity independent of fossil fuels that would last decades, that would have been good for the US economy. It isn't that simple to raise prices on durable productive goods — your customers have to compete against the people who bought the same goods last year at a lower price.

As for the "natural price", the only significant irreducible cost to producing silicon photovoltaic panels is the price of energy itself. Everything else is either literally dirt cheap (silica, alumina, trace quantities of phosphorus) or can be amortized over arbitrarily large production volumes (giant molybdenum crucibles, FIB lithography machines, Ph.D. physicists). In the limit where solar panels are abundant, the "natural price" for solar panels is very nearly the price of the sand they are made from.