That is definitely not true. As a privacy-conscious Internet user, who hangs out in privacy-conscious communities, i can assure you having a fully pseudonymous

That is definitely not true. As a privacy-conscious Internet user, who hangs out in privacy-conscious communities, i can assure you having a fully pseudonymous identity on the Internet is harder now than it was 10y ago because of such policies, and it's definitely IMPOSSIBLE to open a google/facebook/twitter account without at least a phone number. Such policies have definitely not cut back on spam (at least not according to my definition of spam), but have prevented countless legit users like me from taking part in such networks. Retrospectively it's a good thing that these networks don't want people like me, we're doing much better elsewhere. I propose you a challenge: if you can view age-restricted videos on Youtube and create a Facebook group without giving your ID, credit card, address, phone number or IP address... i'll send you a cupcake over mail? :P