It absolutely is not awful. You are doing something wrong then. It's not as good as on macOS of course but it's still great. I get 8-10 hours.
Exactly. This myth keeps being perpetuated, for some reason.
I'm typing this from a ThinkPad X1 Carbon Gen 13 running Void Linux, and UPower is reporting 99% battery with ~15h left. I do have TLP installed and running, which is supposed to help. Realistically, I won't get around 15h with my usage patterns, but I do get around 10-12 hours. It's a new laptop with a fresh battery, so that plays a big role as well.
This might not be as good as the battery life on a Macbook, but it's pretty acceptable to me. The upcoming Intel chips also promise to be more power efficient, which should help even more.
Eh it's pretty awful. I get 8 hours, yes, but in Linux, those 8 hours are ticking whether my laptop is sleeping in my bag or on my desk with the lid closed or I'm actively using it. 8 hours of active use is pretty good, but 8 hours in sleep is absolutely dreadful.