> It’s also surprising to me as I assumed that it was expensive to repair potholes and require special equipment and machines. This makes me think that any unpatched potholes are just a logistic issue since the cost is all labor and coordination.

Cold patch is a temporary fix—it doesn't bond to the surrounding asphalt of the pothole. I don't know much about Portland's climate, and maybe cold patch will work well there long-term, but in areas with harsh winters, any cold patch in potholes will get ripped right out by vehicle tires since the cold will make it more brittle.

Permanent repairs usually do require machinery, as far as I understand.