I wouldn't call it a "lousy job" when it's intentionally designed towards that goal - especially when prioritising form factor, it's the least important element and then only one that can go there.

My mileage is vastly different and I'm constantly impressed by the performance and efficiency of my m1 13" air. Hitting several months of uptime is very common for me and I'm a tmux-session-hoarder and have too many apps running at all times.