iPhone was just an abandoned product line of Cisco so Apple could license it easily. Metro is fifth largest retailer in the world that incidentally sells consumer electronics. It will be like Apple naming one of their products Walmart and asking the lawyers to get the rights because the marketing team wouldn't budge.
But Metro is not a product, it's just a UI style. Metro is also the name of a subway system. It just seems weird to drop it now after so much momentum around it.
I'm sure they could have worked out a deal... this is Microsoft - did they not want to invest in a key brand? How typical. Microsoft shedding brands like a snake molts. How is anyone supposed to trust their platform?
Metro isn't a key brand. Its a brand targeting developers. The adds for windows phone 7, and presumable Windows 8 will never, have never mentioned Metro.
Really I don't understand why you're so angry, if they'd stopped using Windows, or Microsoft or Office you might have a point, but Metro?
http://en.wikipedia.org/wiki/Metro_AG