If the client went to a different designer for his next project, or didn’t pay for all the time spent on revisions, the design was not successful
By that measure Louis Kahn is among the worst architects in history.
To say a design was not successful is not the same thing as saying it was not good. Clients reject excellent designs all the time often for very misguided reasons. But as Ken points out we are in the business of servicing said clients and if the client doesn't get what they want we have not done our job. Sometimes the best thing to do is agree on a kill fee and walk away.
There are many kinds of success. Louis Kahn is one. But think of the standard american paperclip. That is one seriously successful design! If by success you mean ubiquity and such deep penetration into the culture that the design itself ceases to even invite question - almost like air. Agreeing to a kill fee and walking can be a huge success too. I am of course not advocating for any of the above per se. Just saying that inevitably you place your own goal posts and in so doing keep your own score.
IT is interesting to see how this thread has morphed.