Startup Quote from Joel Spolsky, Co-founder, Stack Exchange

I wish that were true. Microsoft disproves it a few times over.

The quote doesn't imply that improving your product is the only thing that works. The quote is that nothing works better than this.

Besides, I think it's fair to say that Microsoft generally improves its products with each iteration. The only possible counterexample to this that I can think of off the top of my head is the XP -> Vista transition.