So pawpaws are always something I've wanted to try, but actually finding them as proven harder than collecting hen's teeth.
From what I've read they used to be a common ingredient for pie—supposedly the origin of "as American s [blank] pie" even—and were a common ration for travelers, including Lewis and Clark.
But at some point they went from a common everyday food to one that's basically impossible to locate (at least on the West coast) and I haven't had much luck finding out what changed.
[The Atlantic actually had a pretty substantial article on this a couple months ago] (https://www.theatlantic.com/science/archive/2022/10/pawpaw-fruit-taste-history/671646/).
The pawpaw's scarcity has far more to do with the fruit itself than any cultural or historical accident.
It's difficult to harvest. The fruit doesn't change color when it ripens, and fruits even on the same tree ripen at different times. So if you're running an orchard, you've got to go through feeling individual fruits and plucking ripe ones. That's a far cry from most crops, which can be rapidly harvested in one sweep by unskilled workers or mechanically.
And it's difficult to transport. Pawpaws quickly go bad after being plucked, especially if they're handled roughly.
Lewis and Clark could easily pluck fruit from pawpaw trees growing along riverbanks on their way west, but it's nearly impossible to get it from the orchard to your Trader Joe's.