Milton,
Your example is built on a couple of false premises ; the first being - ICANN is only the IANA functions operator because of a contract with NTIA ; and the second is- the NTIA transition is to replace the IANA functions operator.
ICANN is the IANA functions operator today based on long-standing agreements with the IETF, the NRO as well as the USG.
In 1998 ICANN was created as a home for the IANA functions and there was no contract with the USG at that time.
In 2000, the IETF signed an MOU with ICANN to perform the technical work of the IANA. This agreement is recorded in RFC 2860.
In 2004, the NRO signed an agreement with ICANN to “require specific actions or outcomes on part of IANA.”
As for what NTIA announced in March 2014, it was not about replacing the IANA functions operator, it was to replace NTIA’s role administering changes to the root zone as well as acting as “the historic steward of the DNS”. In the words of the NTIA announcement, it asks for “a proposal to transition the current role played by NTIA in the coordination of the Internet’s domain name system (DNS)."
Regards,
-- Elise