I was in a computer club in High School. So we were able to play a few games in the computer lab after school. The teacher that headed it absolutely loved playing Descent, but she was also so bad at it that it was pure blind luck if she ever actually hit anyone.

Low latency matters a lot more than bandwidth in any game that isn’t turn based.

I see two approaches that you can take.

1. instead of focusing on what you are taking away. Focus on what you can do with the money instead. Telling them that they can have a new TV with that money is a lot more motivation to say yes than taking something away.
2. Do the scream test. Just cancel everything and wait for someone to scream about not having a services and resubscribe. Repeat every 6 months or so.