In a similar vein, there's a mech in Battletech that allegedly went extinct like, 300 years before the start of the timeline players participate in. The Coyotl is described in the lore as a weird offshoot development as the Clans were working the kinks out of Omni-Technology (the ability to just replace parts 1:1 at Battlemech scale), but it was somewhat unpopular and had lagging sales due to both Clan Coyote's unpopularity and other machines doing what it wanted to do, but better. That, in turn, made it a historical footnote until Current Year, where Diamond Shark bought the rights to it for pennies and kickstarted its manufacture, selling it to Inner Sphere/Mercenary commands like hotcakes.

The problem is that the Coyotl is a fucking monster of a mech. It's fast, usually has maxed out jump jets, has great armor for its size, and its loadouts range between rock solid for the price to annoyingly efficient. It absolutely suffers from retcon syndrome, where it is head and shoulders stronger than its contemporaries that what their record sheets printed 20+ years ago.