Yup. It's pretty common for open source to be used, abused, modified in house and not shared. Just look at Sergey Aleynikov and Goldman Sachs. [0] Further I've seen a shop deploy hundreds of thousands of CentOS nodes to avoid RHEL license fees. Doesn't even begin to scratch the surface of shops not funding FOSS they exploit like OpenSSH, etc. Most of them are stingy, demanding, greedy bastards.
Also part of the reason I grabbed the eject handles on enterprise devops consulting. Although I did manage to fight and win open sourcing changes to net-ldap so that it worked with A-D.
Further I've seen a shop deploy hundreds of thousands of CentOS nodes to avoid RHEL license fees
Such decisions often happen at the engineer level, and it isn't for money management reasons, but rather "avoid purchasing and requisition BS, followed by licensing compliant BS" reasons.
[0] http://blog.garrytan.com/goldman-sachs-sent-a-brilliant-comp...