Thankfully GEO is still a bit self cleaning as Sun and Moon influence makes it unstable - you can clearly see it in orbital debris models, there is a blurry plane shifted ring around the primary GEO stripe.

Still that will only prevent a dead sat in sitting in a valuable spot for ever, it migh still drift the wrong way and require active sats to do avoidance maneuvers, not to mention the chance of two inactive sats colliding.