While reading threads here, it has been established that not all murders had significance for Voldemort (Albanian peasant, Hepzibbah Smith). They were pretty much holders/middle roads to obtaining items for future horcruxes. Excluding cases where Voldemort did not have the luxury to make horcrux in significant murder: Harry (unintentionally), Nagini (did not have a proper body), here is my question:
Why did Voldemort not care about the significance of some of his murders when he was in full power? Why couldn't he obtain items, hold them until someone significant appears, and make a horcrux then?
I am asking because he initially made horcruxes only for something significant: Myrtle - first murder significance, indication on stepping into a dark path, parents - no need to comment, Marvolo - same deal. Why did he stop caring mid-road?