We have dealt with various forms of counterfeits on eBay for pretty much 20+ years now and experience shows that you can report all you want, but the seller has to be VERY blatant before anything happens to them other than perhaps a listing removal. As with other venues, like Amazon and Walmart, they say they are only there to provide a sales venue and can't be expected to vet all listings. Feel free to continue to report them but unless the listings directly affect the various searches people here are using you likely won't see a concerted effort to report the bad apples.
I'm afraid you might be jumping the gun here. I have bought the stamps you're talking about, in fact I'm supplying a scan of a package right now. In years gone by stamps were printed by the Bureau of Engraving and Printing of the federal government. A number of years back this enterprise was shifted to public companies. So when stamps are printed they don't become property of the USPS until after they have been printed, cut into rolls or sheets or whatever, then shrink wrapped. A single coil issue may be printed by several different companies; each one will have stamped its name on the little paper seal around the stamps. (In the scan you can see mine were printed by BCA, whoever that is. I also have a roll of the same issue from AO1.)
The government had very strict controls of what went in and what went out of the printing office. Partly this was because currency was printed there as well as stamps. Private companies, who print many millions of stamps from myriad issues, have very little economic incentive to keep expensive theft prevention regimes in place. I would guarantee that employees of these companies walk off with product all the time. It's not like they are up against the security in a diamond mine.
Printing self adhesive die cut stamps is not an easy process. The Post Office's history making self adhesive die cut stamps is one of multiple disasters over the first 20 years. I see little reason to think that China for example would be interested in making a few thousand bucks here and there on counterfeit US stamps. It would take millions to set such an enterprise up.
The Postal Service has also been so denuded of operating funds that they make no attempt to ensure stamped mail is even cancelled anymore. I don't see them cultivating an interest in stamps that may or may not be counterfeit. Further, I don't think you have made the case yet that the stamps I bought or that other people are buying are counterfeit.
