You're not missing anything, the argument is for how long this duration should be.
The lifetime of the original creator plus $YEARS should be more than long enough for the original work(s) to be made 'canonical'. How is a corporation buying up an IP because it is profitable going to guarantee it remains true to the original author's intentions, or to the desires of fans? If we care about the consumer they should be free to engage with the original works or any derivation thereof as they choose. IP isn't about expanding consumer choice, it's about limiting it - and it certainly isn't a mechanism for guaranteeing the ongoing quality of a series.
The lifetime of the original creator plus $YEARS should be more than long enough for the original work(s) to be made 'canonical'. How is a corporation buying up an IP because it is profitable going to guarantee it remains true to the original author's intentions, or to the desires of fans? If we care about the consumer they should be free to engage with the original works or any derivation thereof as they choose. IP isn't about expanding consumer choice, it's about limiting it - and it certainly isn't a mechanism for guaranteeing the ongoing quality of a series.