Paid To Click, right? Where are the advertisers then? The truth is that almost all PTC sites do not have advertisers. Because no one wants the expensive and low quality traffic a PTC offers. How low is PTC traffic quality? It can be considered and as a waste of server resources!
When you are clicking:

Do you watch the ad?

Do you use escape button or stop, to prevent an ad to load, for faster surfing?

Do you surf in multiple sites at the same time?

It is not difficult to guess the answers in these questions, we have just found some good reasons which are explaining why most advertisers will not buy traffic from PTC sites.The average cost is $10/1000 clicks (bux sites). But this quality of traffic worths for less than $1/1000 clicks. Advertisers are not members of charity foundations and are looking for real humans only, humans who will be interested in (= buy) their products/services. Advertisers are NOT looking for robots or autoclicking software. It is common sense that, robots and autoclickers do not buy products/services, humans only can do that.
And yes, PTC sites are full of robots and autoclickers. Autoclickers also are doing a lot of damage and at PPC programs. But google is google and at least delivers interested visitors (plus the thousands coders who are working there), while a PTC can be a 15 year old kid with visitors who are not interested at all.

Do you want and an example which proves why traffic from PTC is low?
Although it is difficult to prove it with a screenshot (but you can do the same thing), here is an example: An ad at "taketheglobe.com" was about a video at youtube. Of course you know that youtube has a viewer counter.
Total views of this video: ~240.000
Total clicks of this ad at taketheglobe: ~290.000 (!)
Website received in the best case only the 80% of the total clicks!
How many users really watched this video: Good question!
Personal experience: I converted my balance into ads in a scam site. 1000 clicks I "bought", max ~100 clicks my page received!!

An advertiser can't be sure even if he'll receive all the hits he bought. Only a few sites can "disable" Esc/Stop and at least advertisers will receive all hits.

Actually owners don't care at all. The last thing an owner will deal with, is the advertisers and therefore the ads. Most important is the script which controls the fake refs (aka bots).
And don't tell me that you didn't notice that: Most ads in a PTC are other PTC sites with a ref link!!. Also the majority of PTC sites are charging less than paying. Example: $10 per 1000 clicks, while site is paying $15 per 1000 clicks (user click + ref click). Even if a PTC has tons of advertisers will still lose money.

Almost all (99.9%) PTC sites do not have advertisers. Owners have to place self sponsored ads.

Taketheglobe.com used a different model: In order to attract advertisers, owner was selling ads only $25/100.000 clicks (a very good price for PTC hits), but was paying to his members $750/100.000 clicks! Because price was very low many advertisers bought traffic. That's how taketheglobe had 100+ ads. Admin of taketheglobe was accusing bux.to - bots and long payment delays, what else? - but he did exactly the same thing with his site: Bots and long payment delays!! Where is TTG now? RIP...