Well, Sony played a major role in the development of the DVD, so they have had success there. But it's not a Sony-only invention.
According to a couple websites, the following compaines developed DVD:
Hitachi, JVC, Matsushita, Mitsubishi, Philips, Pioneer, Sony, Thomson, Time Warner, and Toshiba.
I really don't think a strictly Sony form of media ever became a force to truly be reckoned with. MD has had a lot of success, though. Especially for bootlegging.