The thing is that ad blockers don't often don't discriminate between acceptable ads and unacceptable ads and just block everything. Even if you put a lot of effort to make your ads better most people will just block them regardless.
Ads which take the form of an <img> tag pointing to an image hosted on the same domain, aren't blocked (at least in my experience).
Oh, and before you scream at me, what about people that simply disable JS, which is basically how all of this works anyway.
I'm not entitled to a free web, I get that, but ads are a failing revenue model due to years of sustained abuse, and that damage is not going to be reversed ant time soon.
However, the need for a list of contractors for works is also required, but things like yellow pages is sort of dead, and if you offer services - eg. you're a freelance photographer, designer, etc. - you need to make yourself visible somehow.