By making your tool Open Source you are not losing out. You are actually gaining because you are allowing the community to contribute.
Recently I wrote about supporting the maintainers of Open Source Tools mostly by donating money. There is another way to support the Open Source community and that is to contribute your own tools and ideas and turn them into Open Source projects.
Scarcity Versus Abundance
Now some of you may have a negative reaction to open-sourcing your tools. You might say "This is my tool, or my baby, or my idea. I want to keep the spoils to myself. If I make it open source, how can I charge for it?" or maybe "It's my secret sauce. If it gets out there no one will hire me anymore."
That's a scarcity mindset. Scarcity is built around this idea of winners and losers. If I give away one of my ideas, then I've lost that idea and someone else has gained it and they are winning and I'm somehow losing. That's certainly one way to look at the world, but it's not the only way.
One of the keys to being successful in life is to have an abundance mindset. Abundance says there is enough to go around. While scarcity says the pie is fixed and we're all fighting over the same fixed number of pieces, abundance says, we can bake more pies so everyone can have a piece.
Closed Fist Versus Open Hand
I used to be a huge Dave Ramsey fan. He would always use the same metaphor when talking about generosity. If you are stingy, it's like holding your money in a closed fist. Yes, no money will get out, but it is not easy for any to get in either. If instead, you hold your money with an open hand, yes some will leave, but it opens the possibility for more to come in.
You might be saying "How could that happen?" Well, it turns out that people like generous people. They are more likely to be generous with you if they see you being generous with others. When you live in abundance, people notice and more opportunities will come your way.
How Does This Apply to Open Source?
We're supposed to be talking about software, right? So how does this apply? Here is a link to a short clip of an exchange I had with Jim Kring on the LabVIEW Experiment, where we talked exactly about this.
It turns out that at GDevCon NA, Casey and Enrique both presented similar tools. One was for visualizing DQMH projects (Panther Dashboard), and the other was for AF projects (Bowzer the Browser). Because they were both solving similar problems they were able to take ideas from each other's tools. They also got lots of good suggestions from the audience. If you look at VIPM, you'll see they both came out with new versions after GDevCon N.A. that incorporated these new features.
By making their tools open source and advertising them, we all benefitted. Casey and Enrique benefitted from the added exposure and the fact that now their tools are even more useful. We as a community benefitted because we now have these tools available with these extra new features. They probably even inspired some other tool developers to add similar features to their tools. In the end, by Enrique and Casey being generous and sharing their ideas, we all won.