Lucas didn't have to make a movie about background info, it's science fiction, people have to try to get it or f*ck off, for the PT the movie was a little bit useless, seeing Sids career taking off.. Big deal.
Lucas shouldn't care if people get it or not.. just kick off a sci-fi action movie immediately about how the republic fell.
The way it turned out now was instead of a major and intergalactic war it was constantly some conflict granting Sidious more power, with TPM being the worst with some random amphibian planet being taken over by petty droids and some gay trade federation. The movie was just an excuse for a basic hero story again with princess and bad guy included.