Why can't supercell focus on other trios in brawl stars?

t e l l m e a l l t r i o s

wild west trio
retropolis trio
shaman trio
pirate trio
arcade trio
undead trio
plant trio
snowtel trio
superhero trio
mystic trio
old town trio
miner trio
junker trio
gift shop trio
entertainer trio

the ones that aren't complete are:
Space trio
Hillbilly ( goldarm ) trio
Stunt trio
Dino trio
Castle trio
Moviestarr trio