lets compare 2 similar T2 static units to highlight how cheap a TML is.
considering that a tml does 5000 damage and a klink hammer does 2000 damage
tml takes 1.01 to build and klink hammer takes 2.03 to build
the klink hammer is 1900 mass and 13585 energy
the tml is 800 mass and 4000 energy plus projectile 250 mass per shot
the Klink Hammer has a range of 115, the TML is 256
TML can even fire quicker than T2 arty
it seems that justifying a significant increase in costs to the TML would be a slam dunk.