They wanted a list of names of people accessing these sites. Texas is the same state that tried to coerce out of state abortion clinics into giving up their medical data. The sites instead decided to not play spy games with their clientele. I'm sure the money would be fine, but you'd also have to build and maintain systems for every state that would want to invade the privacy of its residence, which is a headache.
There's nothing in the law about the state gathering data.
Texas is not the first state with such law. Louisiana, Arkansas, Indiana, Mississippi, Montana, North Carolina, Utah, and Virginia have all passed laws mandating age verification for accessing adult content. I expect this will become even more widespread.
There's probably a market opportunity for the entrepreneurs of hacker news: creating an age verification service compliant with the law of those state, with a strong no-log privacy policy and an API that websites with age verification mandate can use