Frankly the tech for autonomous aviation has been around for a while now. I expect even strong crosswind landings will soon be better handled by a computer than a pilot. But then here’s the problem... Autonomous systems are great when things are going well, but at the end of the day they fare very poorly in edge cases sometimes with catastrophic results. When you’re driving a car you usually follow traffic rules and…
You're correct that edge cases are tricky, but you've made the mistake of forgetting the other possible half of dealing with them that full robotics makes possible: simply sufficiently reduce the cost of edge failure. An aircraft with humans on board crashing is a tragedy, even if it's in the middle of nowhere. In general a cargo aircraft carrying mass produced goods crashing in the middle of nowhere is merely a financial statistic. By far the trickiest part of flying is takeoff/landing and navigation on the ground. But players with shipping volume at the level of FedEx, UPS, USPS or probably even Amazon/Walmart alone can flat out afford their own dedicated airports. With no existing path dependency, they can easily build them quite a ways from population.
This completely changes the calculus and possible responses. If something goes badly wrong on takeoff/landing or at the automated airport itself, it just costs money. There is financial incentive for the players to figure it out, but it doesn't involve anyone else. And once at flight given modern aircraft glide ratios, there is no place on the planet that doesn't have ocean/empty land within glide range. For human flights, ditching the plane as safely as possible, or hopefully making it all the way to an airport, are critical considerations. For a robot plane though experiencing an all-engine out just specifically ordering it to crash somewhere without anyone around is mostly okay (there will be some environmental pollution, but it'd be trivial on humanity's list of environmental damage, and the operator could be fined for cleanup). Robot aircraft could even flat out be equipped with self-destruct systems like the range safety systems rockets have.
So for the specific domain of dedicated cargo craft it seems reasonable that fully autonomous control could exist far ahead of human transport simply by virtue of being more expendable and having infrastructure purpose built exclusively for it in ways that are impractical elsewhere.