Isn’t that generally how trademarks work? Isn’t that why Cisco is allowed to make its own iOS?
Two operating systems would no doubt be considered to be in the same space. Apple licensed the iOS name from Cisco exactly to avoid a trademark suit.
Bad example perhaps (and I just noticed I got it backwards in my comment). But I’m sure there has to be a risk of creating confusion amongst consumers for trademark infringement to take place.
Interestingly Apple also settled with the Beatles' record label after a trademark suit.
One is consumer and the other isn't, so probably no to be honest. If you are apple, better to get the license before you release a product like iOS which is on its what, 10th plus year?
Another example would be cadbury (chocolate company) and another shade of purple. It makes sense - if you go into the shops and see a wall of purple, it is nice if you know what this actually represents, and don't have all the different brands converging on the colour of the most popular brand.