Deleting multiplayer from the Unreal engine can save memory

The market is a lot more complicated than that. But to a first approximation, this is an uncharitable statement of the reality: gaming is a luxury product, gaming is winner-take-all (i.e. the really successful games see 100,000x gross revenue over the median indie game, and people can't play two games at once so player attention is a very constrained resource), and the market consistently rewards novelty over polish. Players still bought Cyberpunk 2077, and then kept buying it after the bug announcements came out; it has sold 30 million copies.

All these market forces conspire to heavily incentivize a game studio to release as close to now as possible with as much game as they believe the players will stomach as possible. There are companies that buck this trend (Nintendo has a tradition of maximizing quality out-of-the-box), but that's where incentives point companies. Minecraft was hilariously buggy (and devoid of features) when it came out; its original developer committed it to a price model where the earlier you bought it, the cheaper it would be, and it became one of the most popular mega-games of a generation.

And the incentives come from players. Helldivers 2 doesn't have bugs because Arrowhead is lazy; it has bugs because Arrowhead wants a billion dollars and gamers can be trusted to hand them over for a product that works most of the time, as long as it's more fun than frustrating.