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...

No. Linux can’t match Mac OS on battery life.

This has been my experience as well. Apple seems to have spent a lot of effort in making their software use very little energy. Check out the energy usage of Safari vs Chrome sometime, for example.

Mine has, older Linux on older Lenovo was not good but also that battery was aging.

New (<1yr) Asus gives me about four hours of 30+ tabs across two indipendent chrome profiles, my heavy editor, multiple active ssh sessions, other nonsense, keyboard lights (on low) and screen at 60% bright.

I think it's very good.

I don't have any firsthand information, but I've heard power management has gotten a lot better for both Linux and Windows and the laptops advertise comparable hours (with reviews not calling them out on it). There are a few name-brand laptops that offer explicit support for Linux distros. Those might gave you a better idea of what to expect.