Storing oil isn't easy, cheap, or safe. I doubt many people have tanks, the know how, or the permits required to store oil. Then once the price goes up you have to move the oil again. It's all really complicated.

If you're seriously curious about knowing more check out https://www.npr.org/sections/money/2016/08/26/491342091/plan...

They are. The world is simply running out of suitable tanks. Yes, that's a thing when global oil demand drops by 30% but production is only cut by 10%. Even if you disregarded every law regarding oil storage and started filling up water towers and tuppaware containers, exactly how many of the ~25,000,000 excess barrels of oil now being produced DAILY do you think that would account for?

> Why aren't people filling up big tanks? I don't get it.

Gas is fairly volatile—even when storing my motorcycle for a couple of months I put gas stabilizer in the tank to avoid draining it.

Because gasoline goes bad eventually.

As far as oil: some are. Often times in the form of huge tankers floating off the coast.

They are and do. The tanks are full.

That's a lot of work to make $20 over the few years it takes to rebound. (assuming it ever does)