The long-distance train routes that lose money are politically essential, and cutting back service on those routes (and making connections even harder) just multiplies the losses by diminishing the usefulness of the ones that remain.
A lot of Amtrak's expenses are fixed & are the same for 1 or 8 trains per day. A station with baggage service needs at least a security guard and 1 or 2 staffers to handle check-ins, ticketing (mostly automated at this point), collect/oversee baggage services, etc.
Density is also a red herring. If you're running a train 3,000 miles, you don't *want* it to stop more than every 50-100 miles, or it'll take a week to arrive EVEN IF it runs at 220mph in between them, because every station adds at least 10-20 minutes (counting deceleration & acceleration time). Open countryside for 80-150 miles is IDEAL, as long as the stations themselves are in cities capable of generating riders.
The real reason the Chief between New Orleans & Florida has gone nowhere fast is because the old route didn't meet present regulatory requirements & was grandfathered in. Rebuilding the track after the hurricane ended the exemption, and the railroad & Amtrak have been in stalemate over who has to pay for the now-required upgrades ever since. It's like a chess game where both players are content with stalemate.
Amtrak could force the railroad to do it, but won't unless FDOT agrees to give Amtrak an absurd amount of money for things that have nothing to do with the Chief. Here's a summary of the conversation between Amtrak & FDOT:
Amtrak: the Chief needs $200 million to have its service restored...
FDOT: OK, I'll get the checkbook.
Amtrak: ... but we won't restore the Chief unless you give us another billion dollars per year on top of that towards the Silver Star & Silver Meteor.
FDOT: No. Florida is the only reason the Star & Meteor even *have* economically viable destinations. We ADD value just by being Florida and existing. Without Florida, those trains would lose more money than the Cardinal & Hoosier combined because they'd lose 95% of their passsngers.
Amtrak: No $1.2 billion, no Chief.
FDOT: Fuck you, go to hell. I have a sexy new Virgin (Brightline) lover who makes me happy & makes my dreams come true.
I'm oversimplifying a bit, but that's the gist of it.
Oh, also... FDOT is pissed as hell about their Miami station debacle. They built Amtrak a brand new station at Miami International Airport to replace their old one in Hialeah, but Amtrak fucked up & signed off on it without noticing that the platform was ~200 feet too short, then left FDOT to try and re-route a street at staggering expense after everything was built. AFAIK, FDOT threw up its hands, walked away, and told Amtrak to go negotiate their own deal with FEC Railroad & Virgin/Brightline to use THEIR new station in downtown Miami if they still want a new station, because Tri-Rail can have the airport station all to itself.