I also finished the course, but the option showed up for me. What's strange though is that after I hit reset the option to launch the exercise system is gone, as is the option in the drop-down. Let me reach out to our Academy team.
Reached out to our Academy team, and I can confirm that once you complete the course you cannot get a new exercise system. You can still practice with the VM though (alternatively: create a new account if you prefer the cloud-based system).