Totally agree that 18 year olds have adult responsibilities and should be treated respectfully. For some, the developmental timeline of executive functioning/self-regulation/time-management is more delayed, and research shows age 25 is when the brain fully develops.
Gaming can be addictive to certain people, just like drinking etc, but it can also be a common interest used to make social connections. Whether you send a full on gaming system to college or not, the kid down the hall will have one, plus there’s social media, online gaming etc. If it’s going to happen, it will happen.
I wonder if the solution is getting busy, having a job, joining clubs, taking cool classes etc? I hear and echo your concern 