> own infrastructure and salaries

Don't they contribute for the development? Or for what is that salary.

Salary for infrastructure admins, etc. Nothing goes to actual development on projects.

https://www.apache.org/foundation/how-it-works.html

> All participants in ASF projects are volunteers and nobody (not even members or officers) is paid directly by the foundation to do their job. There are many examples of committers who are paid to work on projects, but never by the foundation itself.

Mind you, the download mirrors are also free...

same problem with wikipedia / wikimedia foundation

But wikipedia, being a top 10 website, does have significant infrastructure costs.

Wikipedia only has two edits per second[1] and is mostly cacheable. If one wanted to, Wikipedia could be run with a minimal infra cost

[1] https://en.m.wikipedia.org/wiki/Wikipedia:Statistics