Well, yeah. Chewie pretty much completely nullifies Etahns ability, which means your paying a lot of points for nothing.
Not really. You're paying 3 points over a black moon for an equal PS and an EPT slot, the later of which is a massive improvement because it gives you access to push the limit.
Also, Chewie's one pilot. Eathn gives you great utility against large ships and ties (fighters/bombers especially), basically anything with more hull than shields.
Chewbacca is one of the most likely pilots you might encounter at a tournament right now. Etahn is not viable in the meta singlehandedly because of Fat Chewie.
Again, unless Chewie found a way to obscene himself to 100 points, you're getting a target for E'athn
Also again, Eathn unlocks an EPT that gives you the R2-D2 + PTL combo that I know from experience lets him slug it out with fat turrets.
If E'athn is not viable in a turret/phantom meta, Chewie would probably be one of the last reasons. High PS dominance, phantoms specifically, would probably be much more to blame.
Killing a couple Z-95 Headhunters isn't going to win you a game with a Fat Chewie flying around. They're more like a distraction while the Chewie gets in good shots.
Against a squadron with Whisper and Echo together, yeah, Etahn struggles. Against one Phantom and a mini TIE Fighter swarm, Etahn wins by chewing through the swarm in two turns and then working on cornering the Whisper for the rest of the game.
Running PTL and R2-D2 on Etahn means you don't have enough points to play three Rookie X-Wings with him, which is the specific squadron being talked about in this thread. (I guess you could run a Rookie and three Bandits, though, with four points to spare.)