And payload. A drone just can't carry any significant weight.

Those kind of drones are not the kind of drone that can deliver a package, unless that package can survive a ballistic delivery to the ground.

Sure, by shaping the drone into a winged vehicle you can get the payload capacity up and make it move quickly as it goes from waypoint to waypoint on a "delivery route", even in windy conditions. But now you can't deliver the package itself neatly onto the ground adjacent to obstacles like you could with a quadra-copter.

If someone can figure out a reusable payload delivery parachute or something like that with the ability to keep itself on course even in windy conditions to hit a drop point on the ground from a couple hundred feet up, and make it work with packaged goods the size of a small book or video game, then it has a chance.

Not sure what the deleted post is referencing, but Google is using a fixed-wing design. To deliver the package, you tilt the entire drone up to do VTOL. At this point you can lower the package. In theory, it will work and have higher efficiency than a multicopter design. I'm not sure whether or not Google has had any success with it.

That is interesting as hell and I hope it works out; I had a vague sense VTOL wasn't a practical power/weight option for something battery powered.