Additionally, the way trademark law works, the owner of said mark must fight. There's such a thing as trademark dilution. If the owner of a trademark doesn't defend it, they lose legal claim to it.

That's not to say the marks can't be licensed for use. That's why you see things like, "Dolby Digital, and the Double D logo are trademarks of Dolby Labs, used with permission."

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs