>>96753774
if we look at most of the new armies GW has released over the years very few of them actually got a lot after they were made into a faction
most of them get some stuff on release but only admech, genestealers, and now votann got a "second wave" while others were pretty much forgotten. the former two had a real slow down in stuff for them

i think GW understands new factions will just sell well on release and build excitement for the lore but also doesn't feel they're worth enough to follow on that hype
a new faction sells more than actually giving new stuff to an old faction. even if both are seldom popular