It's possible that you could have a company that has 1% paying users that's MORE profitable than a company with 50% paying users. The size of the profit is more important than ratio of paying to non-paying, generally speaking. (And of course, in either case you pay real close attention to the conversion rate and try to get it up higher.)

The total number of paying customers is what determines your revenue. But even then, it's important to track free->paid conversion percentages, e.g. sudden drop offs.