Hugh sent me over this very thoughtful (and kind) post: gapingvoid: there is no "purple cow 2.0".
From the headline, what I thought it was going to say was,
Sequels are rarely purple.
Once you’ve got a Purple Cow, you usually end up milking it, riding it as it enters the mainstream. The danger is believing that as you improve it and add features and create v 2.0, you’re making it more purple. More likely, of course, you’re not.
Diane Von Furstenberg’s first wrap dress was a Purple Cow. The 5,000 varieties she followed up with, the sequels, were profitable but not remarkable. Only when you jump your comfort zone and build the next new thing do you have a shot at the next Cow.