everyone is susceptible to ads. you've just got to catch them at the right time on the right day. if someone has installed an ad-blocker, that doesn't mean that they're totally immune to a sales pitch.
it might just mean that they frequented a site that had annoying pop-ups about loans and timeshares. they didn't like them, so they blocked them. but does that mean they won't be interested in our one-line ads about theatre tickets and music shows?
alright, so they might not buy anything. (maybe they are wary of using their credit card online.) but for website owners a click is all they need. and the chances are that these same users will be perfectly happy to click on the ad to gather more info about the product. (maybe so they can go and buy it down the proper shops later.) but these ad blockers prevent us getting even that.