https://askagamedev.tumblr.com/post/88725419221/why-do-publi...
It doesn't need to last forever. For most games, most of its revenue comes in the first few months after its release. Mitigating piracy during that window is the name of the game.
https://askagamedev.tumblr.com/post/179082079276/when-it-com...
Which isn't to say that Denuvo in particular isn't an absolutely awful, terribly implementation of DRM. But DRM in general works.
https://askagamedev.tumblr.com/post/155630338791/a-question-...