Unless we can get access to the revenue and yield situation we have no way of knowing that Amtrak is being partial to NEC. I know in this forum that is not a popular position and belief in the magic of LD is the favorite theme here. So I will not try to lean against that windmill, beyond pointing out that the arguments being made based on the theme of NEC vs. LD is (a) destructive, and to those that are not invested into a preconceived position are (b) based on mostly hot air, absent more concrete information regarding actual yield, revenue and cost numbers.
Just as an aside, I am not an NEC person. I live in Florida getting hit with significant reduction of service. The way to fix that is not to attack the NEC though that is fashionable escape valve for some who are unwilling to spend the time to come up with an aggressive plan for overall growth of the system, i.e. those that have already declared defeat and now are trying to play the zero sum game. Good luck with that. You will lose all your service, which will mostly affect LD, since NEC, and the regional corridors will get funded some way or the other. just wait and watch.
As it turns out within Florida regional corridors will get funded through public-private partnesrhips as thigns are evolving. Same is true in Texas as things evolve. Many other states may not be that fortunate, specially the more rural ones.