Care more about others user-experience and safety (I primarily use ABP and NoScript to block malware attacks) than the fact that if advertising becomes less effective other methods to pay for websites will have to be developed, so I recommend people use ABP.

Also, advertising isn't "free", there is still a cost even if I am not seeing the money directly leave my wallet every time I see an ad. I would rather the ad supported model died out, the only reason it came to dominate is because there wasn't the technology to support other options when newspapers were first developed.