re: An opportunity for the private sector?
There are companies who have junk removal as an economic goal.
Geosats who no longer can station keep but are working fine otherwise are prime targets of salvage efforts of this kind.
But, I think it should be a requirement to have a means to either reenter or boost at end of life.
As you suggest this can be a downer or an opportunity.
Maybe Congress should make a prize of 100 million dollars for an effective clean up scheme.