Somebody will have to pay the third parties that process the cards. Surely, the age verification will be done by third parties, instead of the social media companies themselves. Who would want to give a copy of their ID to a small social media company that will go bankrupt in a year and then give their subscriber info to creditors? Third party verification will make social media more expensive to own or use.
I read a book, The Coming Wave..., by Mustafa Suleyman. Though not the main point of the book, I was struck by his argument that the creation of AI would mean that everybody will have to relinquish some of their privacy in the future. Regulation of the use of AI will be necessary for the protection of us all. Microsoft recently hired him to head up Microsoft's AI program.