I never did understand why the risk of software audits (remember the FAST wars?) did not kill proprietary software, as the risk to business is so high, not just financially, but reputation risks too. Perhaps it's because licence compliance sounds simple and benign, rather than the minefield and constantly moving target greed has made it.
Historical examples: I can certainly recall that the final and biggest reason for migrating from Netware to NT networking was the fact that the licence restrictions were non-existent in comparison with Novell's draconian rules. Also, we first started looking at Linux at a time when adding a single login to a Sequent Dynix ptx system costs thousands. Some infrastructure development needed at that time was nearly prevented by the cost of the development logins, so I did the research on Linux instead.