It needs to be remembered that, as stated by Jim Matthews who was a participant, these are projected demand for flow studies based on a model and a bunch of data sources for relevant data to feed to the model. They were validated for short terms. It is difficult to validate over a 20 or 30 year period since the data needed does not exist into the future (naturally). Given those caveats, these are the observed major data flows justify certain levels of service by the end of the projection period. It is possible that by the time t+20 years rolls around the projections prove to be invalid, and a new one has to be worked out.
In any event for planning purposes for now this will be one input to what actually gets built. Finding funding for building anything will depend on willingness of the communities involved to participate and local state political haggling, and what not. So what actually gets built may or may not resemble what this particular model projection suggests.
Having said that, I find it interesting that St. Louis - Indy did not make the cut. There are similar omissions of what I expected would be there. But my expectation was based on feelings, not data. So who knows?