Perhaps its popularity "problem" is an advantage. Most DEs have a long way to go before reaching what most end / enterprise users would consider the same level

Perhaps its popularity "problem" is an advantage. Most DEs have a long way to go before reaching what most end / enterprise users would consider the same level of polish of OS X, or even Windows relative to their experiences and needs. In Linux, those of us who use it use Linux on the server for reasons of reliability, and on the desktop for reasons of convenience (similarity). We don't often need an "enhanced multimedia desktop", and don't need the environment burdened by compatibility issues with 5+ year old office programs. Linux is doing very well on the server, and good enough on the desktop - for those that need it.