No one accidentally builds a Billion dollar business - so it's not the case that it just leads you there by default, you need to choose to be that size.

At the same time though, you are right in the market leading nature of it. That is, while building your business the opportunity might arise that you can shift what you are doing and that shift would open up your market to a larger opportunity. Alternatively you could choose not to shift and go for a smaller win.

Why I take issue with the original post is because it is basically saying, if it looks like there is a market opportunity to make a billion dollar company, don't take it.