Licensing for selling anything with a computer in it would cripple competition from small incumbents. They're mostly just regulatory capture for the established players that created the problem in the first place. Age restrictions are also an implicit statement that they are allowed to continue doing the same harmful things to adults.

Meta, Google, Anthropic, OpenAI etc can afford to pay for and deal with licensing. They also created these issues and would very much prefer not to have to mitigate the harm they do to adults (i.e. people with money to spend). Furthermore, it'd be great if they didn't have to worry about small time competitors emerging and growing too fast. Licensing under the guise of "think of the children" is perfect for them.