I guess you don't like artillery?

This is how: https://cdnb.artstation.com/p/assets/images/images/001/819/865/large/manuel-robles-sandwormsbr.jpg?1453246541

Range: https://i.redd.it/6kspraomuij21.png

Arty doesn't auto fire at incoming units, only spawners, and I think worms. The added range on turrets basically makes so spitters don't stand at range and spew on the edge of your dragon's teeth just outside the range of the turrets. Without a higher range, you'd need to have less dragon's teeth outside the wall, so the spitters are forced closer, or have a never ending stream of construction bots flying out there to repair the wall, getting spit on themselves, and then repairing each other forever.

It's quite annoying and this is a fix for those of us that like something to defend against, but realistically by the time you get arty and nukes, the biters are not the least bit of a threat without natural evolution enemies installed. If you do have that installed, having higher range on turrets might just mean you can actually survive non stop waves of 100% evolution groups coming at you, so it's still a win.

Never actually had trouble with spitter outranging my flamethrowers (I have a simple defense-fence, a defence if you will ;-): gun turrets, flamethrowers behind a two-deep (but probably std five-deep in the future) wall , and behind every gun turret and its ammo belt, a laser turret so the gun turrets have a chance to get some action :D)

But still, I'm trying this, although hacked so they have longer ranger than the flamethrower (because "realism" ya'know… flamethrowers in reality have a MUCH shorter range than guns (lasers are of course not a viable weapon system, not yet, probably never in the atmosphere))