[PlasmaKrab]

Well, low-wavelength infrared reflected on targets by the IR searchlight of old-style active night vision devices travel in a straight line at lightspeed as well, so where is the point?
Also, nothing whatsoever in the game will prevent you from having TI/GSR* units with vision ranges up to 255 hexes, for whatever good it will do.
I think, since we already had this discussion here, that Suhiir regrets that there cannot be units with TI sight range inferior to 40 hexes. Vision rating under 40 will not see through smoke as opposed to TI/GSR from 40 onwards.
Personally, I agree that for infantry vision devices, some AT weapons and maybe old low-tech stuff with poor definition, having a lower recognition range and accordingly lower cost could be interesting but I don*t think it is going to happen.

*Yes, TI and GSR are one and the same thing in the game, in the sense that they are just a property that allows a unit to see through otherwise obscuring elements (smoke, vegetation...). So no need to go all physicist, "TI" is what sees through smoke and what sees through smoke is TI, more or less.