It's not uncommon that we get responses back from people we email about support renewals after the first year that indicate the software was never installed, and everyone who knew about it is no longer at the company.

I assume people must be buying stuff to use up excess budget at the end of fiscal years.

At my first startup, we sold exactly one license of our software. A famous news channel bought it for $120,000, the VP responsible for the purchase left for a new job a few months later, and our product was never installed nor used.