And how do you know you're not seeing many old MacBooks? The MBA was launched over a decade and a half ago and it still looks almost identical to a casual observer.
There are huge noticeable differences between a 10 year MBA and a recent one
And as long as you have the Silver color option, a MacBook Air from 2023 looks very much like a MacBook Air from 2014 if you're not stopping and looking closely at it.
If you have one of the colored ones, those date back to 2018 with, again, a very similar design to today's.
Also the M1 has only been around for a little over 3 years. They can't be dying after 4 years because they're not that old.
Where are you getting all this misinformation from? And why are you motivated to be repeating it?