Does not follow. There is no evidence that you can make more money by simply open sourcing your project. In fact, judging from the number of popular, widely used open source projects reduced to begging for donations, it's precisely the opposite. You may simply be assuming as true the same excuses that pirates use to justify their piracy, saying "Hey, I'm giving you free advertising!", completely overlooking the fact that 1) advertising in itself does not feed the creators, and 2) they're primarily advertising it to people just like them, who'll also simply pirate the product.

Look at the companies making the most money in software. Then look at the companies making money from open source software. Note: not companies that use open source or open up some of their non-core code, but those whose primary product is open source, such as Red Hat. There's a few orders of magnitude of difference in revenues. This despite Linux running the vast majority of servers on the Internet and in data centers. Why is this?

While open source proponents like to live in an ideal world where everybody shares their code and collaborates, the harsh truth is that the vast, vast majority of the world will take what it can and give nothing back. That is not conducive to building a viable business when by open sourcing your code, you're essentially make your product even easier to be taken for free.