In my place of employment, anything I create while on company time or using company resources is the property of my employer.
So while it might be nice to say I won't share, boss-man can certainly make it so I must share.
They can't force you to share what they don't know about or don't understand.
It's not about that, it's about the incentive...
Ownership of the IP, as it were, is certainly true, but usually with these tools, most of the battle is documenting it, training people, answering questions, etc., and if you aren't motivated to do that it's very hard to make it happen.
Boss-man actually has a very difficult time turning legal theoretic right into actual deliverables.