When Do You Consider a Franchise Dormant?

[Wman1996]

I would say roughly a console gen (or 5-8 years) is pretty fair.
15 years or more is dead in almost every case. Dead franchises can come back, just like dormant ones.
In terms of Nintendo IPs, some dormant examples
F-Zero: 99 just narrowly saved the IP from its dead status. The fact that it was dormant and then dead for a while means if we don't hear more in a few years, it will probably be dead again.
Kid Icarus: Dead status is rapidly approaching.
Star Fox: If it's not dormant, it's close to it. No new game for 8 years now (excluding the official release of Star Fox 2 over 20 years after completion), and nothing announced.
Donkey Kong: This probably counts. No new game since 2014, no new release since 2018, and the recent Mario crossover is a remake of the original Mario vs Donkey Kong. This is a really weird choice for Nintendo because there have been a lot of Donkey Kong games (platformers, spin-offs, etc.) but DK has gotten sidelined since the 3DS and Wii U.
BioShock is a non-Nintendo franchise that sticks out as dormant.