Our grocery chain has been buying rice and flour in bulk from restaurant supply houses and repackaging them in 1lb bags. Pretty agile if you ask me.
I haven't seen that yet, but at least one grocery chain in my area was offering 25 lb bags of flour for sale about a month ago (or maybe they were 40-50 lb bags).
Haven't been back since to that store since to see if they're still doing it (been slowly rotating through the four we visit regularly), but flour has been available in 5lb bags so long as you're not too picky about the brand or type