Have you lifted or fired one? Once you pull that trigger, you can sense why they are pricey. Those internals are built with multiple ECUs for a near-instantaneous trigger response. Not to mention the fact that they've separated the gearbox to allow quick-swapping of piston systems. They feel real.
Why does a PTW cost as much as a low-end real steel? One word: AMMO
The difference in cost of ammo allows the PTW to be used a heck of a lot more than real steel simply because tactical practice with airsoft ammo costs a fraction of either blanks or live fire. IMO, the price comparison for training shouldn't be focused on the cost of the gun, but in the cost of the ammo the gun uses.
If you want to go the less-expensive route of a Systema, take a look at the Celsius CTW.