As new TLDs come out, this particular narrative is going to be quite common...
"WILL (insert established TLD here) LOSE GROUND NOW THAT (insert new TLD) IS ON THE WAY???"
I do believe that commoditizing the space to the right of the dot changes some things, but I remember .info, I remember .biz, I remember .us sunrise. Everyone said the exact- EXACT- same thing. What they didn't realize is that the preeminence of .com doesn't exist on the basis of some academic theory. It exists on the basis of human behavior. Until you change human behavior, human perception, .com stays where it is.
Do I think the internet is going to uproot its infastrcture to jump around TLDs?
I seriously doubt that. What will be interesting is to see if certain large interests migrate their primary web presence to .(them). If that ball gets rolling, it could gain traction.
I think the flood of new TLDs is going to be the death-knell for all 'second choice' TLDs (.net, .biz, .info).
It may carve out a place for .us, given its inherent meaning and status as the US ccTLD.
Does PETA acquire PETA.ngo?
Probably.
Does it become their primary web presence?
Do they abandon over a decade of marketing their .org, because of some domain name academia that has essentially no practical advantage? Pretty damn unlikely.
Some will, and when they do, fanboys of that TLD will cheer and point to it as evidence of how things are changing, but much like the O.co disaster, in time, it will be proven to be a huge mistake.