Is it usual practice for a Turing Award to be awarded so long after the work in question?
- Knuth got his for TAOCP in 1976, 8 years after first publication.
- Thompson and Ritchie got theirs for UNIX in 1983, 10 or so years after its introduction.
- Englebart got his for his HCI work in 1997, 30 or so years after the fundamental work was done (but just after its universal adoption)
- Alan Kay got his for OOP & Smalltalk in 2003, 20+ years after the first stable release.
- Cert & Kahn got theirs for TCP/IP in 2005, 20+ years on.
And so forth.
The committees in the humanities seem much less concerned about this, and are able to award much sooner.