Yes, when we discuss the Acela vs air travel markets, it is mainly WAS, BAL to NYP and NYP to BOS markets with some BOS-PHL/WIL market share. But the Acela is not just competing against air travel, but car travel as it gets a mix of business travelers and personal travel from people who are willing to pay the higher fares.
Since 2007, Amtrak has incrementally jacked up the Acela prices (with no improvements in trip time), but stills sell the tickets, as demand still exceeds the supply at the peak morning and late afternoon periods.
We don't have the September 2014 ridership and revenue numbers yet, so I can't compare FY2014 vs FY2007, but for fun, here is FY2013 vs FY07 for the Acela and the NE Regionals.
Acela Acela NE Regional NE Regional
FY Ridership Revenue Ridership Revenue
FY2007 3,191,321 $403,571,410 6,836,646 $424,721,134
FY2013 3,343,143 $530,820,821 8,044,216 $568,744,563
Yes, Amtrak took in $127 million in revenue from the Acela in FY2013 than they did in FY2007. Tidy increase. But note the revenue and ridership increase for the Regionals.