(not the author, but here's how I think about it)

Assuming that you're not a commodity product, it all kinda nets out in the end. If you have a competitive market, you have proof that people want your product at a good price, else no one would be in the market. If you execute better than all of your competitors, then you can theoretically take every last penny of that market.

I don't think the competitive pressure changes the decision whether there's revenue to be made in a certain space, though it may change the personal decision if the operating tactics required in a competitive market are personally fun for you the human being.