Are you aware of all the Star Wars licensed books and artwork?
Even when other people gain the right to make derivative works, the cultural concept of canon separates certain works as authoritative from the mass of non-canonical fanfiction.
If Disney did not own copyright over the existing Monkey Island games, and trademarks on the Monkey Island characters and settings, a new game by the original creators of the game would almost certainly be received as canonical.
It would be like Tim Cain making another Fallout game, even though Bethesda owns the rights to the franchise now. Indeed, with both him and Feargus Urquhart together at Obsidian, one might argue that they have at least as much canon right to the franchise as Bethesda, who owns the actual legal rights. Similar with Fargo, Stackpole, and Danforth at inXile making Wasteland sequels, except they actually had to buy the rights to the trademarks. Or it would be like Meretzky making another Planetfall sequel, yet Activision has just been sitting on the rights to do that for decades.
The original rights have long been transferred to different corporate owners, in some cases several times.
There is definitely room to change copyright and trademark such that some rights are permanently invested in the individual contributors to a work, that cannot be quashed or transferred, regardless of work-for-hire status or corporate transfers. When a studio goes under and fires everyone, yet retains all rights that get transferred to a successor company that just sits on them, that isn't encouraging the creation of new works. It's forcing the actual creators to go find new jobs, where they are legally forbidden from continuing their previous work. It might be appropriate to allow some rights to escheat back to the creators, with the successor corporation getting something more like an automatic license.
Imagine if someone like Disney lost the right to draw Oswald the Lucky Rabbit to Universal Studios, who poached all his animators out from beneath him except Iwerks. They'd have to start all over with a completely new character that no one knew about, and directly compete against their own previous work, that would then be out of their control. And then they'd have to see Oswald pulled away from even those poached animators, by corporate fiat and a poker bet by Lantz, only to be buried shortly thereafter by Woody Woodpecker.
Separating the rights from the creatives entirely seems to have been somewhat unwise, judging by the history. Some rights now are literally too complicated for anyone to unravel, thereby preventing not only derivative works, but even just new copies on the market. How bad would it be, really, to just go to the named author (or their estate) to grant new licenses, instead of trying to chase down a corporate paper trail of transfers and contracts?