I don't normally bother posting in threads like this, as both camps are so firmly set in their ways and neither side will give way, but to help inform the debate...
Experts and analysts conceptual Mid-West network looked like this in 2009, as a result of a lot of research, and calculations over actual data, by people far smarter then myself, or probably most people on this board.
10 years to build that network, with further phases planned afterwards, with trains running at 200mph on each of the routes (outside the urban areas where station stops are). Services would be roughly hourly from Chicago to Minneapolis, St Lous, Cincinnati, Cleveland/Detroit. Roughly 2-hourly services would bypass central Chicago and call at O'Hare instead (the map does not reflect the airport loop well I know).
Capital costs for all construction, trainsets, everything to get going was $68.5 billion (2009 US$).
Planned times:
Chicago - Milwaukee (inc. 2 stops): 2:45
Chicago - St Louis (inc. 2 stops): 1:45
Chicago - Detroit (inc. 1 stop): 1:55
Chicago - Cleveland (inc. 1 stop): 2:10
Chicago - Cincinnati (inc. 1 stop): 1:45
Those kind of travel times would blow the short distance feeder airlines out of the water as the system includes an airport stop at O'Hare as well to act as a feeder "airline".
Operating revenue would be an average of $4b per year after a 10 year slow rise as people adjusted to the new system. Roughly half would be customers switching from car, and about a quarter / a fourth would be switching from air transit. Adding in reduced CO2 emissions from cars and planes, congestion reduction, etc etc, the benefit to cost ratio was 1.46%, and a socio-economic rate of return at 6.9%. The system would be profitable (EBIT) after 5 years, in terms of operating of several billion dollars per year, thereby able to provide a repayment to capital costs if required, and able to be net profitable in the long term even after capital costs.