And I always thought (back in my more naïve days) that I read the site in exchange for being advertised to. Point being, the exact details of the transaction were never shown to the visitors. GDPR fixes that by forcing companies to state the terms of this transaction explicitly, and actually ask the visitors if they're willing to participate in it.
GDPR isn't blocking any sites, it's only disallowing a very particular way of getting users to give up their data and then monetizing that data. Nobody is entitled to their business model working forever, and some companies prefer to shut off a large segment of their market instead of updating their business model. It's their choice.