[lamontcg]

Yeah it needs to be made transitive. If you've bought a digital copy of the work from one distributor that should obligate the rightsholder to transferring the individual distribution rights (this needs to be nailed to the wall by the legislature so that distribution rights all carry this mandate by law). If they want to switch distributors then the old distributor needs to be obligated to provide a method of transferring those individual distribution rights to the new distributor. If all this is "too burdensome" (editorial note: cry harder about your profits you fucking capitalist goons) then all the parties can just make it public domain.

[android42]

Yep, and if they want to end distribution altogether or start fresh and still keep copyright, they could distribute DRM free copies for some minimum time frame.