I really don't see your point as you're saying don't put locks on doors and windows to keep honest people honest and if it's simple enough to implement I'm sure the software makers, which I used to be and we did these things, will be willing to implement it, especially if you just hand them the library of code to validate the DRM so they don't have to be bothered writing it.
Sorry, just because DRM can be broken is no argument not to do it as long as it doesn't change the way the online world works for the average Joe nobody will care except the people that get dinged when the click it.
You forgot I offered a multi-prong approach so if they can copy it they can't upload it and if they upload it, it won't display on the other site so even if someone drops in a line of C code to defeat the anti-copy they still have to mess with the image and that's more than most will do as they now realize they're physically altering things, they're IP will be tracked, they could be fined, pay $100K in statutory damages, yada yada because they've deliberately done something that can get them sued opposed to clicking PINIT.
Like I said, simple technology, supply the libraries, make it robust and show the comprehensive nature of the solution.
BTW, technology like PicScout and Tin-Eye can be used to identify the images even in screen shots as they crawl the web so worse case you can find it being used, even in a collage situation, as I've used those tools and they are amazing.
It's like bot blocking, no matter how hard you try you can't stop everything but you stop so much garbage that what's left is really hardcore scrapers, just like DRM busters, and you have crawling technology to find out where your content goes if they really want to bypass all the blockades set up that stop people who don't kick down your door when locks are installed.
This will stop normal people from behaving badly, educate those that don't know any better, and highlight the scum who will go to any length to get what they want without any consideration to the copyright holder.
Why wouldn't you want to stop the bulk of the image abuse just because others can go ahead and defeat it? Makes no sense not to stop what's easily stoppable because that makes the rest of the problem at least manageable which is the best you can hope for in scraping situations.