It has! I've been using Ubuntu on a thinkpad x1 carbon (2017) for almost a year. Battery life is between 6-8 hours everyday use including work. Probably see between 8-10 if I'm not doing any programming
Similar experience on a Thinkpad T440 with a 1080p screen swap, I can easily go 5 hours before I need to swap to the big battery, which buys ne a few more hours. Games seem to halve that though...