NFS 4.1 isn't "highly vintage", the RFC is from 2010.
Even if this exploit only touches completely new code, my point still stands that windows has multiple layers of archeology which were designed when security was an afterthought.
Some of these are preinstalled with Windows, use networking and run as SYSTEM (WMI, spool) others are used by enough components in windows they will never be removed yet it doesn’t seem they are undergoing any development (COM/OLE)
But NFS probably isn't the top priority for Microsoft, the implementation of NFS 3 felt sketchy, so in that way it's not overly surprising.