Given that a reroute is not likely either, I think we should push for either a connecting train or thru cars on such a route rather than rerouting the entire train. Amtrak already struggles to compete with driving when it comes to driving time so I'm not eager to add multiple hours to the route when Chicago would still generate significantly more traffic than St. Louis and a thruway connection to STL is already available.
This topic has me wondering how many routes don't take the shortest route between endpoints. Come to think of it, there are at least 8 LD routes that take longer routes than necessary. Below are the ones I can think of along with a faster alternative route.
-California Zephyr (UP across Wyoming)
-Cardinal (LSL Route)
-Coast Starlight (via Central Valley)
-Empire Builder (bypass Grand Forks)
-Silver Meteor (FEC)
-Silver Star (FEC, A-Line through Carolinas)
-Southwest Chief (Southern Transcon via Texas Panhandle)
-Texas Eagle (via KC and OKC)
Many of them take the longer routes in order to serve major cities, such as the CZ, CS, and SS, which makes sense especially considering how few passengers ride end to end. It would be nice if the system was large enough for more of a variety in LD routes, but I don't forsee it in the near future. I don't know how track conditions have changed, but the 1969 schedule for the City of San Francisco was a full 9 hours faster than the current CZ.