Where's my catcher?...

 I still don't understand why there is no self-propelled, autonomous grain cart.  (I call it a catcher) It would be controlled by the combine operator, be self-contained and on tracks. I'm thinking a half-cab like a spotter tractor for trucks.

Sure Kinze has the remote control cart, but why haven't we put engines on grain carts like we did for sprayers?

In all the IoT possibilities, I think this is #1 for grain farmers.  This is not a flying car.  It would be astonishingly productive, with a high marginal value during harvest. The three person minimum (combine, cart, trucks) would go back to the dump-on-the-end minimum of two persons, allowing father-son, brother-brother, and husband-wife pairs to keep a combine rolling continuously.

Instead we get drones and multi-hybrid planters - both answers looking for a problem.