Heyho,
those monsters you are describing often just existed in the purple or legend+ astral layers. So as I didn't see them in the current layers aswell I suppose you will have to wait to face this kind of monsters again.
7-12 Etherium is... well luck based but I think it isn't that good, 'cause there are multiple ways of getting gold beside that, like burning keys, leveling reinc, doing Anomalous Region (1900g astral) with every reinc (maybe do the second one in s2 too), doing caravan etc.
You can also farm astral nuggets while you are farming etherium that maybe would increase your gold income, as you can use them to buy gold or chests.
But to answer your question: I think it is still worth it, but you need to have luck or a good killrate/min. So enter hub, pull everything with shots from visor, then kill everything with artillery or AoE-Shots from cannons. After everything is dead, go to next hub quickly and do the same etc. Remember the hubs where almost just little mobs are spawning so you should enter this hub more often, than the others etc.