After Uncle Sam walks away--i.e., IANA stewardship transition--anything is possible--
Beyond just the RIRs and IETF wanting to strip ICANN of its intellectual property (IANA trademarks and domain name), consider this:
ICANN's budget, staff, policy-making, time, attention and problems, are now dominated by ICANN's "horribly implemented" new gTLDs program which represents less than 2% [correction] of all domain name registrations globally--truly a "tail wagging the dog" situation. Do the math:
"Overall at the end of 2014, 130.6 million .COM and .NET domain names were registered. Of this sum, 115,600 000 registrations were .COM and 15 million in .NET ... The new domain extensions [new gTLDs]... [were just] 2.3 percent of the global gTLD market ... Overall, VeriSign estimates the number of registered country code Top-Level Domains [ccTLDs] to be 134 million domain names. Worldwide, VeriSign has identified around 288 million registered domains and growth of 6.2 percent compared to the previous year ." Source: translated from German: https://www.internetx.com/news/com-und-de-bleiben-auf-wachstumskurs/
288 million total domain names registered globally Q4 2015--
116 million .COM domain names
15 million .NET domain names
134 million ccTLDs domain names
265 million domain names are either .COM, .NET, or ccTLDs = 92% of all domain names worldwide
+ 3.5% (10 million registrations) for .ORG domain names = 95.5% all domain names globally.
Leaving just 13 million "left-overs" which are comprised of the "other TLDs" + ALL new gTLDs
These "left-overs" represent 4.5% of all domain names globally--1.6% [correction] new gTLDs + 2.9% "other TLDs" (as of Q4 2014).
Last year ICANN estimated 33 million new gTLD domain name registrations would occur in FY15 (ending June 30, 2015), subsequently revised to 15 million new gTLD FY15 domain name registrations. Where are we today? Less than 5 million new gTLD domain names have been registered in FY15 according to ntldstats.com (6.2 million less the 1.4 million new gTLD registrations prior to FY15 -- before July 1, 2014).
Remember, the Numbers and Protocols communities--RIRs and IETF--can leave ICANN on very short notice pursuant to their agreements with ICANN, and the ccTLDs have no "binding" contracts with ICANN. Verisign's .COM and .NET gTLDs and its Registry Operating authority, pre-date the existence of ICANN, and it is at least debatable whether ICANN could prevent Verisign from joining the IETF, RIRs, and ccTLDs, in utilizing a new IFO (IANA Functions Operator) or even establishing a new Internet root, particularly since the world's largest corporations all utilize .COM domain names--see: ICANN, IANA functions, Ultimate Mechanism of Accountability, A New Root.
So yes, it is an interesting question.
"In the Domain Name System (DNS) naming of computers there is a hierarchy of names. The root of system is unnamed. There are a set of what are called "top-level domain names" (TLDs). These are the generic TLDs (EDU, COM, NET, ORG, GOV, MIL, and INT), and the two letter country codes from ISO-3166. It is extremely unlikely that any other TLDs will be created."--Jon Postel, March 1994, RFC 1591