Small timeline correction: the rate changed in January, they only announced it in November.
I don't know that it was specifically Epic alone, and Apple certainly wouldn't outright say "we're doing this to help strengthen our ongoing legal arguments with these specific companies", but between Epic, legal complaints from other high profile companies like Spotify, and antitrust investigations in EU opening all at the same time just before that announcement time it seems an awful large coincidence to have a press release drop about how they're cutting the commision for 98% of developers to 15% but managing to leave 95% of the total revenue at the 30% rate with no influence from these external factors at the time.
I don't know that it was specifically Epic alone, and Apple certainly wouldn't outright say "we're doing this to help strengthen our ongoing legal arguments with these specific companies", but between Epic, legal complaints from other high profile companies like Spotify, and antitrust investigations in EU opening all at the same time just before that announcement time it seems an awful large coincidence to have a press release drop about how they're cutting the commision for 98% of developers to 15% but managing to leave 95% of the total revenue at the 30% rate with no influence from these external factors at the time.