Open Source definition ( https://opensource.org/osd ) says nothing about community involvement or accepting contributions. It may be common, but it is not necessary, required or even hinted at in the license.

Open source is not a philosophy, it is a license.

For many it is very much a philosophy, a principle, and politics. The OSI is not the sole arbiter of what open source is, and while their definition is somewhat commonly referred to, it is not the be all end all.