Monopoly on usage of a name not so much, although how it is implemented (or enforced) has substantial problems too. Companies regularly hijack commonly used words as "property" and/or push their monopolized names to the general vocabulary (e.g. iPhone, iPad, App Store, Googling, Kleenex, Xerox) especially in the USA and then literally police how people can use the words.

Yes, they should lose the "property" if they do so, but in practice they lose it decades too late if even then.

Also trademarks being sellable means that at any moment the product with a trademark can have nothing to do with the original holder, partly defeating the rationale.