Couldn’t disagree more and Amtrak's own numbers back it up. Click on the attachment from my previous post above. I think those numbers slipped through the cracks honestly. Costs to run NEC 737M, the LD network 151M.
Fixed costs aren’t going anywhere.............
One last point on 3x daily service. It was tried before and failed spectacularly for all the above reasons.
But it does open the door to 2x weekly service as on VIA Rail.