A few questions as a non LP user:

Why don't propane distributors use very large bulk propane tanks situated on farms in these times to help buffer supplies.

They could perhaps get supplies in cheaper by ordering larger amounts (prior to crisis and peak heating season) Distributed tank network makes for shorter runs to residential customers. Gives a very large buffer capacity in times of high need like this.

Local elevator has a deal with co-op where the elevator has a huge tank for running dryer. Co-op also pulls out of this tank for making local deliveries.

Yes more work but I'm sure it's metered both ways and prices are probably also set according to fill and removal dates.