8 months (though I imagine sales may have tanked in June when they announced the transition to Apple Silicon, so Apple probably only got 3 months of sales.)
But it was in fact the fastest intel MacBook Air - and it still is.
What few people outside Apple (or even inside given Apple's notorious secrecy) probably realized in early to mid 2020, even after the WWDC announcement, was how great the Apple Silicon/M1 MacBook Air was actually going to be, and how it would transform expectations for performance and battery life in a fanless laptop.
Perhaps Apple should have offered a trade-in scheme like they did for the Lisa/Macintosh XL. I wonder if they offered upgrades to the buyers of the October 1999 Power Mac G4 (PCI Graphics) which was replaced by a better model only two months later.
Let's also recall that the 2020 MacBook Air launched in March 2020, at the onset of the pandemic. Nobody knew how serious that would be and what the impact would be on tech manufacturing, especially in China. It was the last major launch before global lockdowns set in and it wasn't clear when the next one would be possible.