Just remember how many AAA or big name titles use Unreal as engine. Those can sell millions of copies at 60 per copy. And even if they have much better rate it is still probably half a million to millions a game.
With numbers like that, collecting a half-million dollars from even ten blockbuster games per year is probably not even worth the time and energy it would take; that would be 0.1% of their revenue, which, relatively speaking, is basically nothing. That whole business wouldn't even show up on the balance sheet.
FWIW basically no established game developer is using the standard terms epic provides. If you’re in a situation where you have a high degree of confidence you will owe Epic money it is worth reaching out in advance.
True, but I also imagine that Epic isn't bargaining down the rev share too low. Or, companies are fine paying 8 or even 9 figures upfront in anticipation of such success in a custom contract.