It will become your problem once more and more of the sites on which you rely make the decision to "charge membership" or "starve and close your website".
He might prefer paying in cash than with his privacy; then this change is not a problem but rather an improvement. You could argue that the walling-off approach would reserve important content for rich people, but then it is the seller's fault who fails to extract money from his visitors in a proportional manner. Rather than walling off the content you could use the "tip jar" already mentioned. It works for some people. I do not belive in limiting ones audience, I believe it to be counterproductive.
They would not. They are a required for that kind of interaction. Displaying static text however, does not. It is either really bad web engineering or intentional degradation. Both of these lowers the value of your content for me, as it requires me to jump through hoops to selectively enable content on your site. Unless you offer something truly unique, I will go elsewhere. It is called competition.