The US will never have a high speed rail system like France, Japan, Korea, China or even Germany.
The US relies more on plane and car travel unlike France, Japan, Korea and China. Nobody really takes a train anywhere now days. I mean, from Ft Lauderdale to DC the Amtrak is about 25 hours. You can drive there in 14 hours or fly for less than $150 which is less than the gas your vehicle would require. (I believe NYC is about 30 hours and the flights are the same price.) And Amtrak is really not high speed per se. If I am going to spend 25-30 hours traveling somewhere, I better be using foreign currency when I get there.
All new infrastructure would have to be built since the majority of rails in the US are privately owned. Acquiring land, building new rails that can support the higher speeds would be expensive. On the flip side, countries like Japan, Korea and China have to rely on rail systems because they can't really handle high numbers of vehicles. This is why you see countries like Brazil, Korea and Singapore regulating cars on their streets through different means (banning cars based on the last number of the license plate on certain days - Brazil -, making cars horribly expensive to own - entitlement to car ownership - Singapore).
