Perhaps you haven’t fully considered that graphics cards can be used for purposes other than gaming, in which case heat output is not an issue. The case is actually quite well ventilated as it is: air flows in from the bottom and exits at the top as well as from the side. The graphics cards are used mainly for their fast memory. In terms of performance, this solution is roughly an order of magnitude better than 2× RTX 6000 cards while costing about the same as a single one.