The Series S is basically an X with a weaker GPU

If it was just a GPU difference, you'd be right it should be easy to just run it less pretty. But the memory limitations are the real issue. The X has 16 GB of memory and the S has 10 GB. And worse, the memory performance is drastically different. The X has 10 GB that runs at 560 GB/s and 6 that runs at 336 GB/s, where as the S has 8 GB at 224 GB/s and 2 GB at 56GB/s. (I did not miss a zero on the last value)