The government is going to save porn -- that is so l4m3 ...
If people have to apply for a PAID access (AVS) -- it will be in restraint of free speech (in the USA); first amendment.
If sites need to pay for the AVS -- your costs will increase.
If ISPs get involved; the price of your service will increase, ... want pornsite access? +$5 a month.
Tube ads will be worth more perhaps -- better qualified referrals and guess what: the tubes won't have the traffic volume and will demand more revenue -- site owners will pay more -- I have no idea if they will really net more ... You will have to put more money on the wood to find out -- that is a given