They're called ash can films. studios license the film rights to a property from the copyright holder, and usually, there's a contractual obligation to produce a film based on that property within a set number of years, or the film rights revert back to the owner. If a studio can't get their shit together within that period of time, they have to make something, so they'll make a half-assed version of the film and give it no more of a release than they're contractually obligated to make to retain the license, then either try to make something good in the time allotted or sit on the rights for another cycle.

Look at the fantastic four for example. there were three separate films that bore that name (not counting the one that actually managed a sequel), all ten years apart. there was the richard donner version in the nineties that was never intended to be released, the two movies in the two thousands, and then fanfourstic in the 2010s.