That’s some ground-level hanging fruits - do you know any piracy websites the size of Amazon or Netflix? Sure as hell I do not.

Piracy websites are usually pretty limited in scope. Places like some shady porn repos, pirated games and movies, etc. Of course there are some giants like thepiratebay but even they are nowhere as large as the ones you mentioned.

All of these, especially the big players, have high costs of maintenance and advertising. Just like their “legit” counterparts in size.