This is hardly Linux's fault. ASUS just didn't bother writing (proper) drivers. I have a HP laptop that has support for RHEL, and therefor Linux distro's in general.
I only had to install TLP for power management and I get the same battery on Ubuntu as on Win10.
The thing is, as a customer, after a certain point I just don't give a crap. Like, when I was a teenager it was super fun to spend entire days fixing esotheric problems with hardware and rebuilding the kernel to suit my needs, but nowadays I want to hit the power button and work. Linux is not that, at least not for me, I do use Mint daily on an older Dell laptop and that is 90% fine but for any "serious" development I would always use my Windows machine + VS.
I think you just have a bad SKU of a laptop if Linux gives you 1hr and Windows only 2.5hrs.
Message to OP try 16.04.2 LTS (or a later version) and I think you'll find very different results with Asus laptops and Ubuntu.