That’s because battery life was pretty mediocre across the board, with Apple occasionally squeaking out a bit of an upper hand on the Air. Most laptops were in the same boat, aside from gaming and workstation laptops but battery life has never been the point of those.
That changed dramatically with the M-series Macs. People didn’t start caring because Apple did, but because it meant no longer being tethered to a wall, being able to do a lot of outings without a brick or charger cable at all, and on extended trips being able to get by with a little phone charger instead of a the usual huge ungainly brick.
One of the primary objectives of a laptop is portability, and long battery life is an objective upgrade in that category. Not everybody needs it but for those who do it’s difficult to give up once you’ve had it.
EDIT: Another advantage of that higher efficiency is that MacBooks can run at full performance without being plugged in without it obliterating battery life. x86 laptops universally throttle when untethered and while this can be disabled, they burn through their batteries much more quickly.
For someone who is actually out and about all the time, this is life changing.
If you just sit with your laptop tethered at your desk all day, they why would you ever care?
I think most people who are so wowed by Macs bought just a garbage Windows Machine (e.g. almost everything from Asus and Acer) before and then splurged the money for a nice one, so obviously it's so much better in comparison.