That's the problem. As time goes on, all the really popular shows will have left Netflix (Friends, The Office, Frasier, Always Sunny, etc) and all that will be left are Netflix Originals.
The vast majority of those are not premium shows like The Crown, You and Stranger Things, but straight-to-DVD caliber bilge that will initially entice users because of the netflix branding, but turn them off once they realize it's low quality. You can't keep commissioning new programming forever while keeping the price at $12.99/mo. or whatever.