Move Dead bases to higher leagues
I think that if dead bases are moved to higher leagues, then it would cause players to want to gain trophies, which supercell clearly wants everyone to do. The higher the league, the more dead bases there would be there. The actual amount of trophies the base has would not change, and the amount of available trophies would always be the minimum for the league the attacker is in. The owners of those bases probably would not care, and if they did they would start playing again. I don't know how good of an idea this is, but Its better than just completely getting rid of dead bases.