Open Source software has changed the world.
This very site is using open source software. You can run your entire company on open source software and thus get going for a tiny fraction of what was required before open source. I'd therefore say that it has enabled the explosion of startups and technology advances in the last few years.
Building a company around a free product is a different issue. Some sell support, some run on donations and many projects have a paid versions to support the organization that grows and guides the product. Companies are often happy to support open source projects because it ultimately benefits them too. I've contributed to projects because it is easier to make improvements to an active project to improve the product for my own use than to either fight a vendor to get some improvement implemented or to create the product from scratch.
But if you are asking about how to build a profitable organization around an Open Source project, then you have a hard road ahead. You have to offer some real value in the "free product" to get a large enough user base. And then find a way to add different value in exchange for money.