Sparky, if one wants to push the envelope of art, copying an existing work of art does not seem to push anything. Warhol elevated a often overlooked common place object as art, Prince and Levine took existing art and merely copied it. They didn't really alter, change or re interpret it. The fact that they acknowledged that they appropriated someone else's art is not noble on their part but simply stating the obvious, and maybe avoiding litigation by doing so. If they were looking to argue their concept why not write about it, why instead copy someone else's work and sell that work for far more than the original artist received for it.
I do not consider myself a "modern day" warhol dissenter, I understand the significance of what Warhol did. However what P & L did was not remotely as significant a concept. I think what they have done is over conceptualize, over intellectualize,over rationalize and justify ripping off someone else. As for them making their copies appear more degraded, bad color, etc.,well they're starting with misappropriated copies of the originals to begin with, and justifying that the image quality is poor is in itself their means of expression could just be a way of not having to even make any effort to better the image quality.
More importantly if this type of work is accepted it will become the new benchmark for acceptable plagiarism and the next conceptual artist who wants to make a name for him or herself will simply push that line even further. Where does this end up? This is the digital age, someone can buy a print, scan it and produce surprisingly high quality copies, almost indistinguishable from originals. What next? Sell those prints side by side against the original artist's work and then justify their theft with the precedent of Prince and Levine? What about just converting "Citizen Kane " to color, or the "Godfather" trilogy to B&W and selling them as your own work.
Call me old fashioned, but to me copying some one else's work, changing it ever so slightly, signing your name to the bottom of it and then writing an essay to justify and rationalize your actions is not art and not creativity. To me it shows a lack of integrity and creativity