Sony just stopped producing game discs. GTA 6 won't ship on one. And the same summer, Atari is selling 39 brand new cartridges for a console from 1977. When the PS4 launched, under 10% of game sales were digital. Today it's about 85% on PlayStation. The disc was already a rounding error, roughly 3% of PlayStation revenue, so Sony killed it, cut the manufacturing cost, and routed every sale through its own store where nothing can be resold. Here's what that actually bought players. Ubisoft…