If The Last of Us Part I generated the same gross revenue on the Epic Games Store, Naughty Dog LLC, Iron Galaxy Studios would keep approximately $92,230,954 - that's $11,493,723 more than on Steam.
At this revenue level, Epic's concrete platform fee would be $12,440,585. Epic charges 0% on the first $1 million in annual per-app revenue and then 12% on the remaining amount. On GOG (30% cut), the developer would earn approximately $73,270,077.
Note: This is a hypothetical comparison. Actual sales volumes differ significantly between platforms, and Steam's larger user base typically drives substantially higher sales.