"on the long term this looks like a major mistake."
Thank God you didn't make a mistake like this, where you build a company around a profitable product making millions of dollars, but might one day feel bad because there are other customers who can't buy your product, who likely wouldn't buy your product anyways!
Heh, so maybe I was overly sarcastic in my tone, assuming you were just criticizing from the sidelines. :)
I suppose the less sarcastic version, is that Sketch is just a happy accident. A class project, that turned out to be very close to something solving a real problem for a significant market of people willing to pay money for a solution to that problem.
Thank God you didn't make a mistake like this, where you build a company around a profitable product making millions of dollars, but might one day feel bad because there are other customers who can't buy your product, who likely wouldn't buy your product anyways!