You also understand that there have been plenty of 'normal' balanced ships since wave 3 like the Z-95 and Defender and M3-A Interceptor and Starviper that would be playable in this meta should they not have to deal with a 13 health turret behind a wall of damage mitigation or ships that can gunner their HLC blasts.
I went 4-0 vs fat turrets with TIE Defenders in a Regional Championship. Three of them were undefeated before they played me, the other one I faced in the top 8. The fact of the matter is, if you maneuver better than a Turret to consistently draw arcs on them, then you'll have a large advantage in the ensuing dice-off. Ion Weapons also let you set up turns of predictability, where you can bring much more firepower to bear than you could just trying to guess where they'll be every turn. Fast blockers like TIE Fighters and especially A-wings can do similar things. There are lots of tools to deal with turrets. If you chose not to use them, that's your choice.
If you really want to get a sense of good and bad moves a turret can make, set up a table with your squad and a fat turret squad. If you've got Vassal, do it there, because it's a lot faster and easier. Make the moves for "your" squad, then look at all the moves for the fat turret. There are good ones and bad ones based on asteroid location and possible maneuvers by your squad. Do this a bunch of times, and you start getting a sense of where your squad wants to be in relation to a turret. Throw in an Ion Cannon or Ion Pulse Missile, and restrict optimal turret positions even further. Yes, the turret will almost always get a shot, but if you do it right that shot will be a consolation prize. To be fair, fast ships are much better at this than slow ships, because they offer more choices in blocking and drawing shots on a eluding turret. To bring it back to the OP, this is one of the reasons why BBBBZ doesn't seem to be having widespread success, It's not very good at bringing its firepower to bear on the most common tough targets.
Points aren't equal in this game. Some points spent will be worth well more their their cost against certain targets, but be worthless against other targets, such as Gunner vs high or low AGI targets. If your squad doesn't have some points spent that are good against fat turrets, you can't really expect to beat fat turrets most of the time.