The web is hacky and getting anything to look and feel just right is a pita more often than not. So people use band aids like bootstrap, sass, react, angular, jade, custom build systems requiring lots of set up... frankly speaking I'm baffled people put up with piling up layers and layers of abstraction and somehow consider it easier and, god forbid, the future of the desktop. Seems like a great example of 'easy vs simple'.