I think in terms of game production, software licensing usually isn’t the largest cost center for a project. Proprietary software isn’t a concern as much, given that games traditionally are “shipped” and then completed. (Note that this changes as games that are more online service-based with live operations, rather than a specific release date and a “final” copy sent for production; the internet has changed things a lot)

You’re more right than you think about multiple versioning systems, although keeping synchronized becomes an issue. Perforce is a bit of a boon for management, as they get a GUI for versioning across a multidisciplinary team.