National labs sign "cost-effective" deals. NVIDIA isn't cost-effective. Aurora (at Argonne) is all Intel GPU. Aurora is also a clusterfuck so that just tells you these decisions aren't made by the most competent people.
[1] https://ladailypost.com/los-alamos-national-laboratory-unvei...
When you're a national laboratory and your wallet is taxes from fellow Americans, it is very important that you find a balance between bang and buck. Lest you get your budget slashed or worse.