Fair enough, maybe it's just that the headline is misleading. No doubt, that inflection point does matter... But I wish he'd been clearer in saying that that's what he's talking about.
But even if we acknowledge that that inflection point is important, what conclusion is he asking us to draw from it? Does acknowledging or not acknowledging this point make much difference to any strategic or tactical decision a hypothetical startup founder is going to make? I mean, if the OP had made a point about "this is how you know when to go raise outside money" or "this is how you know it's time to shut down the "profitable" startup," then I'd have found this valuable.
But even if we acknowledge that that inflection point is important, what conclusion is he asking us to draw from it? Does acknowledging or not acknowledging this point make much difference to any strategic or tactical decision a hypothetical startup founder is going to make? I mean, if the OP had made a point about "this is how you know when to go raise outside money" or "this is how you know it's time to shut down the "profitable" startup," then I'd have found this valuable.