The main conditions for qualification as OSS are that the product must be free to redistribute, source code must be available, and that modifications and derivative works must be allowed.
Nobody controls development.
Invariably, OSS products are tightly controlled either by a single individual or a small developer group. Apache is run by the fiercely meritocratic Apache Group, and PERL is controlled by Larry Wall. Anyone can change the software, which eventually becomes unstable. Changing OSS for one's own use is always possible. With most OSS projects, only a few individuals have the necessary access rights to integrate code from third parties or to release new versions.