I very much disagree with you. US 71 between Kansas City and the northern terminus of I-540 in Arkansas have very high traffic counts.
Missouri has it's act together, like always. Arkansas can't even get a 2 lane bypass built within a reasonable amount of time (Bella Vista Bypass).
Trust me, it's not pork... Have you traveled it? It is a rural corridor, so to speak, but look at the traffic counts. There you go.
I invite you to come down to NW Arkansas... and SW Missouri. Experience the nightmare here in NWA... I have never seen such inadequacies. Keep in mind, this is not a major urban area, so to speak.
And there is accident after accident (on I-540/Future I-49 in NWA)... It's a a common occurrence... And the cable median barrier they are constructing will only provide a "band-aid"... It's rather sad.
I commend Missouri for seeing the potential of I-49... Good for them!