You can't be serious. "The standard was adopted, therefore it must be able to be implemented in any or all systems?"

NIST can adopt and recommend whatever algorithms they might like using whatever criteria they decide they want to use. However, while the amount of expertise and experience on display by NIST in identifying algorithms that are secure or potentially useful is impressive, there is no amount of expertise or experience that guarantees any given implementation is always feasible.

Indeed, this is precisely why elliptic curve algorithms are often not available, in spite of a NIST standard being adopted like 8+ years ago!