Linus brought DVCS to the masses, but to pretend there wasn't more at play than simply open sourcing a project and hoping it all works out is complete rubbish. People have families to feed. Closed source is not inherently evil.
It takes a unique situation to produce something like git that's product is beyond the sum of the project itself.
Open sourcing those patches rather than keeping them to myself made a difference that was greater than anything I imagined. Similarly, the impact of making ZFS open source far surpassed the expectations of the original team at Sun. I think that making any worthwhile piece of software open source will lead to adoption beyond the scope of what its authors envisioned. All it takes is people looking for something better than what previously existed.
As for closed source being inherently evil (your words, not mine), how do you fix bugs in closed source software that a vendor is not willing to fix? How do you catch things like a hard coded password that gives root privileges? How do you know that the software is really as good as they say? It is far easier with open source software than with closed source software. Closed source software is a bad idea.
I grew this to a place where I could pay salaries. Doing so was super super hard. I had a lot of scary nights where I thought I couldn't make payroll. Just building up to a place where the next payroll was OK was a big deal for us.
So open source it? When you finally got to the point where you can pay people without worrying all night?
I get that you see that open source is the answer, and it is for some stuff. For me, jumping on that years ago was asking too much.
At work, many of my newer colleagues have backgrounds in closed source software development. We are developing software that has no exact analog to existing software, and we hope that it will have a big impact. If it becomes as important as we think it could be, then bit keeper vs git is a fantastic example of why our work should be open source from the start.