One could argue Epic is trying to demonstrate Apple and Google are basically Visa and MasterCard. ( That is purely my guess, personally I dont see Epic has planned a decent, long term strategy other than simply charging into battle ) And in EU Visa and Master had to lower their CC processing fees from their 3-5% in US to somewhat sane %. Similar case in AUS as well.
I wonder if Tim Sweeney saw the opportunity from DHH / Hey.com, decided to take a bet and jump onto it. Simply judging the flow from Twitter and people within his own circle. ( or Bubble )
I actually have no problem with Apple or Google charging 30% for gaming. I do have problem with Apple charging business like Fitness class, Online Email Services, Education or all other Services simply for access through their Apps. Had it been something like 5% to 10% I think everyone would have been happy to pay. It was estimated 80% of App Store revenue were from Gaming. Apple could have lower their non-gaming cut without substantial loss of services revenue stream.
But it seems there are large enough group of Americans thinking Apple can charge whatever they want. It is their platform.