I mostly gave up on this several years ago when a woman, last name Starbuck, down in Oregon was sued and had to close her cafe because she called it, drum roll please, Starbucks. In other words, you don't own your own name! So if I started a business and called it Tiffanys, I'd be in deep do-do.
Also the Kingdom of the Mouse got Congress to extend the length of copyright protection, from 75 years, because they were about to loose coverage of their flagship character. SCOTUS ruled that it was OK because it was still for a limited time, thus Constitutional. Since corporations now live forever, [1] presumably they will get Congress to extend it again when the new deadline approaches! Sounds unlimited to me, but what do I know.
hank
[1] 'Twasn't always so, to put some NG content in, the RGS expired, as a corporation, in December of 1939. It had been incorporated for 50 years in 1889 and nobody bothered to renew the charter. So if somebody had bought up the stock and bonds and tried to reorganize it, they would have, I think, had to get a shiny new charter first to do so.