This gives something of the history: http://en.wikipedia.org/wiki/Sailor_Moon_%28English_adaptations%29 (The "Saban" version was apparently by Toon Makers, not Saban.)

Pioneer only ever had the DVD/VHS rights, and they didn't lose them to anyone else - the North American rights originally acquired by DiC expired after ten years, and Toei subsequently locked down the series. It looks like they started re-licensing to some other countries in 2010 (starting with Italy), but haven't granted a new North American license yet.