I used to work at a place that was next to a storage facility. We would go out to our cars and see the storage facility cutting the locks off of yet another unit. 95% of the time it was full of pure junk. They had auctions all the time.
I rented a trailer recently and that place also had a HUGE storage facility. The had a list of 75 units that were overdue on rent and were up for auctions in the next few days. The lady there said a lot of people have a household of trash and they will just rent the place for a month and that is cheaper than a dumpster.
There are new facilities being built all over the place. It is just astonishing to me how much people will pay to store crap. Crap that is often not worth two months rent much less years of rent.
I suspect it will be a profitable business for you, but it will be a lot of work.