> They don't even have basic reading proficiency until age around age 7 or 8.

Some develop advanced reading proficiency well before that, and the more they read the more likely that is to become the case.

Every child is different, but the more you assume they can't do certain things, the more you'll find that to be self-fulfilling.

(That said, that makes an argument for extensive access to reading materials, not videos.)

This is completely wrong. Kids can easily learn to read at age 5. A child who is working on "basic reading proficiency" at 8 is very behind and has not been well-served by the people responsible for raising them.

Yes, but still I would argue that books are the more appropriate reading material :)

Yeah, 100% with you on that.