Nothing expensive about it, it's about reducing the workloads for devs. Currently they do a PC SKU (GDK), and a Console SKU (GDKX). If they do a universal "Xbox" SKU, the devs wouldn't mind if license is universal as no additional workloads. So it would be a PC SKU that is scalable to various hardware but can also be optimized to presets for fixed spec hardware.
So future more powerful hardware can get presets or just play everything scaled up. Automatic backwards and forwards compatibility but still optimized to 3 to 4 sets of fixed set hardware every 3-4 years.
That means they could do a 24 CU, 48 CU, 68 CU Consoles, then have Handhelds, Laptops, PCs using the exact same chips.