You're still forgetting the inconvenient fact that Amtrak does not have enough qualified T&E crews on that route to cover a daily service. You'd need approximately twice as many conductors, engineers, etc. Even if you could take an Albuquerque or Minot or Omaha crew and fly them to El Paso, it would take a few weeks to get them qualified on the route.
If I understand correctly if a UP crew is traveling an unfamilar route on the UP network they need a pilot for the first two or three runs or so, correct? So what I'm curious about is why would an Amtrak crew that normally runs on UP track would need a
few weeks of preparation before they could even start service? Not saying you're wrong, I'm just trying to understand why this would be so different.