Voadam
Legend
I think it's worth pointing out that these other game companies are swimming in different waters, as far as markets and market power, than WotC. I think a lot of smaller companies are willing to invest the effort in these offerings and risk the loss of potential revenue because it (or at least forego a likely paltry revenue stream) saves them in marketing expenses. I suspect it serves as efficient and cheap marketing on their part. They need that community service to keep or expand their niche among niches market.
WotC, with the biggest game titles in market and media share and as part of the Hasbro conglomerate, has the resources to run broader marketing and actually has the a ghost of a chance to turn something like character sheets or power cards into a revenue-generating product. So they do.
WotC itself does Star Wars SE doesn't it?
White Wolf is number 2 for RPG companies in size isn't it?
I think Mongoose is currently the biggest producer of current OGL stuff. I think it is in the top 5 for RPG company sizes.
White wolf does sell character sheets. In print and even in pdf form. RPGNow.com