I worked for a company which used Redis at the prototyping phase, but then wrote own database to improve performance and resilience. The company wasn't selling

I worked for a company which used Redis at the prototyping phase, but then wrote own database to improve performance and resilience. The company wasn't selling an end-user facing product, the product was a distributed filesystem. My take on this is that most companies don't have the expertise to build systems like databases, and even if the costs would otherwise suggest such a development as desirable would be simply afraid of doing it.