I heard once that all these live-action films are a way of renewing the copyright/proving Disney is still "actively using" them for film and not just movies. Is there any truth to that idea?
Copyright has an end date. Which keeps getting extended but that won't happen forever. When you adapt an IP, anything new you do has new copyright. With time running from its creation. Winnie the Pooh is out of copyright, but Disney's version isn't yet. As it was created more recently. Remaking and doing new versions of the Disney IP muddles the waters because there are always new additions. When the original Disney versions leave copyright, anyone wanting to do something based on that will have to ensure they don't do anything that came from a more recent Disney version of the IP. So it just complicates it.
While it's a long time since I read up about it, I believe Disney is going to be looking at trademarks as a way to protect its IP. Trademarks don't have an end date as long as they are being used. So various elements of the Disney versions, a word, name, phrase, symbol, design, sound, character, color, or color scheme can be trademarked as long as they are associated with a brand. I don't think this has been tested yet. I understand Mickey Mouse is considered so closely associated to Disney that when Steam Boat Willy comes out of copyright. Anyone using it won't be able to use the Mickey Character. As it would be seen as passing off as Disney. As the character and design is so closely associated to the brand Disney.
The issue comes to other characters not so closely associated to the brand. The attempt will be to have the Disney brand of the IPs. They will show that they are constantly using their trade mark elements. Which will protect the uniquely Disney version.
So once the copyright for Disney's Aladdin expires. Someone can use it, but they won't be able to use the trademarked aspects of Disney's version. It can't be made in a way where it is mistaken for Disney's version.
This is what I understand the idea of protecting their IP to be. I could be a bit wrong, things could have happened in the years since I learnt about this stuff.
They key thing with trademarks are you have to keep using them.
For people like me that live in shit hole countries. Ever notice how brands that don't operate in your country often have pop up stores or events? It's so they can claim they are using their brands trademarks in the country. So no one can take their trade marks, for the day they may one day decide to start operating in the country.