enforcement is up to the ag, so yea. they could just ‘ignore’ the law.
In practice, there’s no real mechanism to force it (especially if Congress is unwilling to impeach & convict). But legally speaking, the Take Care clause of the constitution obligates the President (through his executive) to enforce all laws passed by Congress. Ignoring it would be unconstitutional.
There’s no solution or implementation, and the law in place actually forbids social media from requiring ID as the means of age verification. But who knows what it’ll end up actually looking like, because even the politicians didn’t bother figuring that out before passing the law in under a week.