There's a fair bit of survivorship bias in there. Few games are considered "great". Roughly half the games get canned during development. So while it may be impossible to make any game in a reasonable amount of time without creating some sort of mess, nobody would argue that a worse process isn't detrimental to the project. It could be the difference between a game being good-but-flawed and a masterpiece, or between "not salvageable" and "shippable".

Moreover, the "survivability" of the process goes beyond just one project. Jon got so burned out on the C++ language that he'd rather create his own language for the next project than use it again. If he didn't have to do that, he'd likely be working on the next title already.