I used to work for Comcast Internet/Wireless support. Supervisors were just normal reps who dealt with angry people better. NEVER actual sups... they DO have jobs outside listening to some angry person yell and then giving a discount... since that's all you'd get anyway, thus meaning a normal rep could do it.
Sadly, for all Comcast customers out there, *I* would fix the issues. I got fired for being WAY too slow on calls... but I fixed EVERYTHING if it wasn't 100% a line issue or device or their comp. And even when it was their comp, I still usually fixed it.