Tim Bray brings up an argument I have heard too often - time to market kills your competition. I think it is important, yes, but it does not kill competition. There are too many important examples of time to market not killing your competition.
Let's look at some of the most important high-tech goodies out there. Internet Explorer for web browsers, Google in search, iPods in music players. All of these did not exist when competition "had the market". They came in late and took the market by being better in different ways. IE was easier to set up in the OS - you might say illegally easy to set up, but there you go. Google was simply easier to find what you really wanted. iPods were all around superior devices to any other mp3 player I used - much easier to navigate.
But the key aspect here is that these players were different and significantly better than their competition. If you have the market, and you capitalize on that by learning and adjusting quickly to what people need, it's yours. But if you stop innovating, it's just a matter of time before folks flock to something else.