How about... People are paid as age verifiers. Win, win. More jobs, lower chance of data being stolen, maybe more awkwardness if you came across your partner on the other end of the teleconference call.
Or, how about this, bring back porn theatres. Industry gets paid from ticket sales, you have a ticket person who can ask for ID.
Also, is porn really that damaging to kids? I remember when there were videos circulating from beheadings and that was far more traumatising.