You can't explain Figmentmania with just a great mascot design or just being Disney branded. That isn't giving you those sales or historic line waits in this competitive market. He sells largely because of the attachment to his original ride that gave you a reason to like him.
And that's the flaw. Figment is an IP, a high-selling IP. But unique compared to all their others in that his popularity is centered around a ride that hasn't existed for a quarter of a century, and either the fans rode it long ago or are younger and fell into the trendy mystique of it after riding the modern version. Every other IP either you can rerun a film or series indefinitely to new generations or you can ride a beloved ride right now, where here you have to hope a small set of Disney fans in the WDW realm "get" the character after seeing what he used to be on Youtube. That can't be sustained forever.
They need to get he needs a flagship central media again or that lightning in a bottle will dry up. If it's the ride restored (most preferred), a tv series or film, a game, multiple, whatever. Do something that can be indefinite so new fans can always be made. Cameos in comics or Speedstorm are nice but are only a temporary refresh, not a long-term IP support. And if they do nothing then that current ride doesn't sustain the interest he has now and it'll decline. If they replace it with Inside Out they lose all reason for people to care for him, even if he cameos. If they want this lucrative IP to continue or even spread beyond its niche instead of fizzle out they need to do something. And that mostly being what everyone has been saying for decades.