.com definetly will be precious, but new gTLDs are here to stay, and they do have a lot of potential, a lot of them will take years to really develop, but the .com will still be a unique neighborhood, more for transnational corporations, it will almost be compulsory for them to have their name in a .com, and also having their own gTLD..
there will be a lot of confusion and trademark infringement, .com will profit from these problems,but also will be affected..if you take a unique word, example, I'm the owner of lala.com, and someone creates lala.shoes, most likely they'll visit lala.com first, but it will take a potential product that my word can be market for,..so the first pages of the phonebook is .com, all the rest of the pages are the TLDs, but there are TLDS that have a huge clip in the phonebook like abc.xyz