Linking to John Storey's 6 definitions of culture, here are the reasons Disney is such a huge example of pop culture:
Well liked by many - in 2019 7 of the 10 top billing films were owned by Disney
Defined by what is not high culture - It is accessible to everyone and can be seen everywhere
Commercial - there's no point in me listing the thousands of merchandise they have. Or the productions going on created by them. In my own experience I have seen many of their shows and own some of their merchandise, including: mugs, figurines, costumes and pictures.
Authentic culture of people - see the youtube link on how disney ruined culture. They have made many films that exploit specific cultures around the world. They even own National Geographic and have episodes on their streaming site
Exchange and negotiation - Again, there is no point listing the endless amount of companies they have bought.
Post Modern - they have been producing films since 1937 however there is a clear shift in what disney produces since they started using 3d animation. The films are a lot less dark than the originals and you can tell they try not to offend people. A prime example of that is when they added a black character to Frozen 2 which was set in 1800's Norway. See the SNL sketch below

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