>>8582395Trademark laws. You can't copyright a word, so you trademark it's usage exclusively for your brand of products. Toys can "transform," but that doesn't make them a "Transformers™ toy." However, because of how trademarks work, if a word becomes a common usage phrase for specific objects, it loses its power as a specific reference to a brand, and can eventually fall into regular use without the need for ™, even if it's not a common word. That's why it's a "Nintendo™ Console," otherwise everyone would sell "Nintendos." Transformers is especially at risk for this since Transformer is something very common outside the toys, so they need to take any precaution they can from others trying to make their own Transformers.
It's a little more complicated than that, but the general idea is if their brand becomes a common use word, their ™ goes bye bye.
