I understand that what Steve Blank (and also Joel in his famous article) refer to is rewrite of existing applications with a lot of customers, something that brings a lot of cash to the company already.

Also, it seems that you describe a rewrite you did by yourself: the dynamics of a rewrite by a single person are quite different I believe, and are more likely to be successful (unless that's one guy who rewrite everything and ask other to support it, which sadly happens too many times).