> Very expensive "deal with keeping track of which developers relicensed their games" problem.
There is tons of licensing issues in the gaming industry under the surface that causes problems all over the place. An extreme example would be Sega's mistakes with Sonic.
Sonic 3, despite not having him in the credits, contains some works by Michael Jackson. That has complicated things tremendously in re-releases, so much so, that Sega has re-released that game far less than Sonic 1, 2, and CD. Sonic Origins, the latest re-release, contains redone music from prototypes rather than solve the licensing quagmire.
But that's not the only licensing quagmire. Guess why the Sonic movies don't have almost any soundtracks or sound effects from the game? According to the Directors, it wasn't a thematic choice, but a legal one. Sonic CD's re-release on smartphones had a similar issue with the opening scene having the vocals removed, because they were from an obscure band that went through a series of legal changes, acquisitions, member changes... This is actually a big problem with re-releases in general. Hunting down who actually owns the rights to a series can be a mess when acquisitions are involved; and you'd better hope the new owners at the end of the road are reasonable and not eager for a quick buck.
And to top it all off, just look up the Kenneth W. Penders story, which single-handedly took advantage of Sega's lax copyright protectionism to "steal" almost 200 characters right from under Sega's feet. Nintendo is no doubt looking at that, and the Sonic music issues, and thinking... man, this is why we protect.