I have a little different take than the article...
I have only been to one streaming site, and it was a horror of cam hell. Yeah, newest movies! And equally yeah, "looked like shit" isn't even touching the surface. Ugh.
P2P downloads, however, were invariably better quality because they involved Blu-ray or DVD rips, or caps.
So what I conclude here is that the law is having an effect. Instead of relatively clean, watchable rips, pirates are now driven to the horrors of cam streaming. So in this regard, it's working... and would explain why people are buying after watching ("Good story, now I'd like to actually see the movie!).
Of course there must be better streaming sites than the one I saw, I'd bet they're still not nearly as good as P2P type downloads. I base this on my experience with Netflix, which is legal streaming, in HD, and looks like absolute garbage. So, once again, the law may have increased piracy, but it's making it harder to get quality. And after a certainly amount of time, I'm betting lots of people will just plain tire of the crap and we'll see an even larger bump in pirates buying legit copies.
-Pie