I think the Carinthia TRG is so expensive, because it has a relatively sophisticated cut and a faultless make. And it's developed in Austria and made in Slovakia (or perhaps like some of their products in Moldavia). But the main point surely is the price of the Goretex fabric. I think it's made in Germany.
If we look at the sleeping bags and padded clothing, the Carinthia products aren't overpriced, although 100 % made in Europe.
But if we look at the Goretex sleeping bag cover we get a shock. Especially if we are used to the military surplus prices.
But both are made by the same people and offered by the same enterprise. And most of it is bought by the German army (and other NATO armies as well), what means that the stuff isn't overpriced. The German army could also employ other contractors like Gustav Wahler or especially Feuchter, who delivered them thousands of German made Goretex bivvy bags and rain suits.
The TRG was developed together with British special forces. Carinthia built in what they wished. It's quite possible that it's the best military rain suit in the world.
And if you compare in the end the price with Asian made civil products, that's of course a bit more expensive.
An Austrian made Mercedes G / Wolf that's built to the specifications of the Austrian, Swiss and German army is also a bit more expensive than usual Asian pick ups. I don't need it but it's surely not overpriced. Austrian Engineers simply don't serve you for a cup of rice.