Have no issue finding them at my local Sam's club, they sell them in a six pack for $20.. But yes, No refillable propane cans have gotten scarce, the normal places I typically buy them at no longer have them..
I believe part of the problem is a metal shortage, metals like steel and aluminum has caused a lot of shortages of pretty much anything made of those metals..
Refrigerators, most any home appliances, lawn mowers there are shortages..
Soda cans, yeah, hard to find consistent supply of some brands and types so it wouldn't surprise me that there may be a shortage of disposable propane cans..
See
Supply chain shortagesHeck, if you need lumber or building materials, there is major shortages there and the prices have nearly tripled since Jan 2020..
Needed some 2x12x8 ft treated boards to fix a shed floor, paid $25 per stick back in Dec 2020, those used to be less than $11 each..
Been hearing rumors of 1/2" 4x8 sheets of plywood well over $55 per sheet!
Now we just may end up with a another TP shortage since there is a cargo ship stranded (run a ground)in the Suez Canal and is blocking ship traffic causing ships to be rerouted adding a half million miles to the goods trip around the blocked canal..