If you will forgive the intrusion of a first-time poster, I think there are a couple of related facts about passenger rail in Europe that are ofter overlooked, but which may be instructive for rail development in the U.S. First, unlike Athena emerging from the head of Zeus, European high speed trains did suddenly spring forth fully formed from out of nothing. Rather, they are the culmination of many years of work, and were "built" on a foundation of what we would call conventional rail.
Second, those "conventional" trains (actually faster than Amtrak in many cases) still exist. For instance, I believe such trains in France ply the rails under SNCF's "Corail" brand. They serve passengers who are less time-sensitive and/or more cost-sensitive. They also serve many locations not served by high speed trains, and feed passengers to those trains.
What lesson is there in this for the US? While I certainly agree that the development of frequent-service corridors is where the great bulk of passenger rail funding should go, I'm a bit dubious of efforts such as the HSR initiative in California to build a high speed system where, for the most part, no rail system now exists. Without the base and continuing support of more traditional rail service, I think it questionable whether a high speed system will succeed on either an economic/operation (and I do not mean profitability; as James J. Hill recognized long ago, if you want to make money, transport pigs, not people) or political basis. I believe, we should certainly move toward true high speed in the NEC, where a proper foundation has already been laid. In most other areas, I think it best to provide improved conventional service. This would provide transportation alternative to more people relatively quickly, and would start building a foundation for possible future HSR.