I'm all for pushing back on the idea that just because it's "old", that it's useless and needs to be replaced. Lots of old machines are still perfectly good at a lot of stuff, and can be had and upgraded for cheap, which is awesome!

However, there's no way to slice going from a M1 MacBook Air to a ThinkPad T480 as anything but a downgrade. The screen is worse, the CPU is worse, the battery is MUCH worse, it's thicker, heavier, the list goes on. If the author of the post is happier with his new laptop, that's great, but this isn't really a path it makes sense for anyone else go follow him down.