It really doesn't matter what you use, I use Blender exclusively (and the only one in studio), but it's good to know basics of 3Ds Max at least. Like m_asher mentioned - "studio's pipeline can include scripts and plugins (that can be exclusive to the studio) that only exist for certain software packages", I think this is…
Which is why you should know the basics. Studios won't expect you to master every package out there, but they will expect you to know enough to fit your work into their pipeline. And since studio's pipeline can include scripts and plugins (that can be exclusive to the studio) that only exist for certain software packages,…