Trademarks only cover very significant uses. Microsoft can (and apparently did) trademark X in connection to the Xbox, so competitors can’t make a game console called an XStation or PlayStation X, but people not making video game consoles aren’t affected.
[Edit: Man, Lemmy is weird. I deleted this comment right after posting it because I thought it was redundant. I only undeleted it because I saw it was the top-rated comment in its sub-thread.]