This is interesting. What about the Texas law makes it impossible for PH to comply if they were to otherwise decide that that they wanted to (which of course isn't likely)?
Set up controls, if anyone bypasses them, you have expensive litigation and potentially existential financial penalties.
Or don't and lose the revenue of Texas folks.
Interested parties will go out of their way to bypass any rules PornHub does set up, and PornHub bears the brunt of any successful such attempts.
If you did your honest reasonable best, a suit shouldn't go anywhere. Systems aren't perfect. They aren't really expected to be either.
Given the way the porn industry historically operates by addicting the young and the huge levels of abuse towards women. I'm not holding my breath for good faith efforts.