Note the "commercial rules" you mentioned include provisions for a thing called competition and another thing called choice.
Linux, and much of the software that is written for it, fills a niche. Only in "recent" times has Linux emerged at all as a player in the Desktop market, while Linux and BSD have quite an established presence in the server market and related fields. These systems are free, but often times the support or certification to accompany them is sold commercially (Red Hat and Novell are two major players in this). While Linux may not have the "market share" that Windows or OS X have, that fact in no way should determine the quality of the software written for it. This is a completely subjective matter.
Some find Windows better than OS X, some find Linux better than both. Some find IE better than Firefox, some don't. Some find GNOME better than KDE, some don't. Some find hot dogs better than sausages, some don't. See where this is going? "Better", in general, is a subjective matter, a matter of opinion.
Try not to make blanket statements regarding subjective matters. Everyone is entitled to their opinions, but these should not be espoused as fact. Peace.