Uncle Bob, I can't say why you don't see a lot of wild plum thickets, but if there's none along the fences or roads in straight lines, it is because nobody's planting them. It's too bad. Also, the "wild plum" seedlings you buy at the nursery now are, I'm told, not necessarily 100% wild. They have some cultivated-plum genes from having been planted in yards as pollinators. If you want real wild plums, you have to go deep into some uncivilized place.
Now, Bob, if you went out on your bike and came back with a 5-gallon bucket o' plums, what did you do with the bike?
Surely you aren't telling us you somehow mounted 40 lb. of plums in a giant bucket on your bicycle.