"Is an OS all about GUI and look & feel?" Considering 95% of the world don't care about anything but how something looks and whether they can interact with it

"Is an OS all about GUI and look & feel?" Considering 95% of the world don't care about anything but how something looks and whether they can interact with it in a way that makes sense I would suggest that it is, to a large degree. They also need a good foundation of course but too often do people in the OSS communities confuse having a solid foundation with having a winning product.