That's what people said about Quark XPress, but failing to have a smooth transition to MacOSX doomed them. It didn't even have to be a very smooth one, since Adobe took forever to ship the ancestor of creative suite.
More, I suspect there's a delayed effect where people are still holding on to their non-subscription copies of CS. I'm a heavy Illustrator user; I'm still on CS 5.5, but when the time comes to upgrade it won't be to Illustrator CC.
So you can see the logic behind Creative Cloud: Adobe have both prevented this behaviour, and struck against piracy. They're clearly betting that this will outweigh the reduced sales, and that Photoshop/Illustrator/InDesign are so essential that few people will pass it up. I'm not convinced they're right.
A known torrent site begs to differ!