A few issues I have with that:

• Who decides what is “adult content?” Sure, today it’s boobies and penetration, but a year from now it’s Michelangelo’s David and Botticelli‘s Birth of Venus. A few years later it’s any text containing anything but male-female couples, and then anything that criticizes The State. Once you open the door to internet censorship, you won’t shut it again.

• How will they ensure anonymity while still establishing viable age verification? If I have to give personal identifiable information to establish my age, then they will forever be able to track me - see what sites I visit, what I read, what I buy, who I communicate with. The internet suddenly becomes a lot less accessible when I know I’m being followed everywhere I go online.

• Not all sites will be able to age-verify, and they will be able to stop all the sites which don’t. Suddenly all the seedier, less reputable, more dangerous, and darker sites get more attention. The cultural impact that could cause would be horrifying (hell, how much influence did 4-Chan have in making trump appealing to certain demographics?) Sure, governments can play “whack-a-mole” all the live-long day, crushing those sites, but they’ll just pop back up, or more like it.