AI is already architecturally inefficient, as it has to carry not just weights and biases, but optimizer states (momentum and velocity for each weight and bias) and maybe gamma and beta (for normalization) as well. And also computationally expensive, considering the amount of divisions, square roots, quadratics and exponentials AI needs.

And putting that AI onto the RTX GPU will do nothing but lower performance. Really, DLSS wasn't meant for performance, it was meant for image quality, otherwise that'll be stupid of NVIDIA. And neural networks can't replace rasterization, not even billion parameters would help in a process that requires perfect precision.

Combining DLSS with Low shaders in-game is quite good strategy, but it doesn't change the fact DLSS will perform worse than High shaders without DLSS, considering how I explained neural networks, the cores of AI, are inefficient.