There are plenty of problems that go away by themselves because there was no problem to begin with. The micro-managing managers that suddenly get a bright insight that needs to happen now, only to completely forget about it a day later. The impatient people who can't wait 5 minutes before the annual reports are generated and sent out to their inboxes. There are plenty of solutions out there just looking for a problem that doesn't need to solved.
Sounds like you've never worked a computer help desk. Lots of times people would call in and the problem would stop as soon as they got halfway through explaining it. They just weren't patient enough.
Sometimes people would call in and through the process of describing the issue they would figure out exactly what they needed to do, they just needed to talk it out.
System down for an hour to convert data while XYZ software was shut off to upgrade from 1.2.3 to 2.3.4 last week while you were not answering email? Solution, don't upgrade XYZ software from 1.2.3 to 2.3.4 again, seems simple enough.
Also in the real world random end users are free to request absolutely any imaginable feature or capability which management via budgets or goals have already declared will not be done. So waiting for some higher up to deliver the bad news when you can't deliver the bad news, is perfectly valid assuming you have a reasonable excuse. Oh you'd like it quadruple redundant as long as that redundancy is free? Yes I'd like that too, but it isn't happening.
I can't count how many tickets I've closed by saying "This is lower priority than X, Y and Z. We will address it, but not this very second." Then, two weeks later, going over to the person to gather more information about the ticket, it's suddenly not required any more.
The operative word is "some". The OP was not implying that "All" problems resolve themselves, surely you must have experienced something that you thought was a problem only to discover a bit later that it was not?