As to the completion of I-57 to I-20 my comparison was versus I-69 in Arkansas. I agree with your maybe on that one, but it is still seems more likely than I-69.
A contest between which will be completed first, I-69 thru AR & MS or a possible but not officially planned I-57 extension down to LA, sounds like a contest between two impossible scenarios. Which will happen first? Pigs sprouting wings and flying or Joan Crawford coming back from the dead with an army of zombies to terrorize Hollywood?
The I-69 projects through Southern Arkansas and NW Mississippi at least have had official plans on the books for decades now. The problem there is just a general lack of funding for all those projects. And the cost estimates for the Great River Bridge keep rising.
It would be easier financially to make an extension of I-57 Southward from Little Rock, consuming I-530 to Pine Bluff and Southward. But there are no official intentions or discussions about making any sort of Interstate extension South of current US-278 between Warren and Monticello. The current AR-530 route South of Pine Bluff has remained an unfinished Super 2 with a pair of disconnected segments for a long time. Intersections are at-grade. AR-530 is basically nothing more than a rural 2-lane highway with more gradual than usual grading. AR DOT doesn't appear to be moving quick at all to double-barrel the route and add limited access exits. They basically can't seem to get that 30 some odd miles of Interstate route finished. Adding another 80 miles of road South of that to Monroe seems far more improbable.
69 will never be finished in MS, AK AR, or LA.
I agree fully!
and what purpose would 57 serve in LA?
What purpose would I-57 serve in LA? I-57 could complete two separate corridors. One would wind up in Baton Rouge (US-425 to Natchez and US-61 to Baton Rouge and I-10.) The other to Alexandria and Possibly Lake Charles.
First US-425 to Natchez. Secondly US-165 to Alexandria. Hurricane evacuation routes. If you were in LOUISIANA, you would be hearing this. Right now, the discussion is all on I-49 to NOLA, I-10 widening & rebuild, Solving the traffic dilemmas in Baton Rouge, a new bridge in Both Baton Rouge and Lake Charles. (Additional in Baton Rouge. Replacement in LC.) Some possible projects in Shreveport and Bossier City PROPER.
Beyond that the discussion ends, When this list is completed, the next project would be a new North / South Project. I-57 would fit that mold. I 69 doesn't. It would skirt into the state above the hurricane line and the Northeasterly direction is all wrong...
I stand by my idea that I-57 gets to I-20 before any of I-69 is built to interstate standards in Arkansas and before any of I-69 is built north of I-20 in Louisiana and likely west of I-49 as well.
If it were Texas, it would likely wind up as 4-lane divided highway. Louisiana and Arkansas will build freeway.