This is true to some extent, but the best, most successful open source software is nowadays to a large extent made by for-profit businesses developing it for their own use but sharing it with the world.
There is a strong correlation between “is this kind of software mainly used by businesses vs. individuals” and “does this kind of software tend to be open source”. Hardly anyone uses proprietary version control or web server software anymore. But (other extreme) in the area of video games, nearly all of them are still proprietary and probably will be for a long time. Software such as web browsers or office suites sits somewhere in between, both kinds exist there.