I do not really see much of an impact on the Big 3 or ccTLD (used in the way they were intended).
COM/NET/ORG grew organically with the internet. That is the major difference between those (3) extensions and what came after. They all share broad awareness, usage, and credibility.
To most people the new extensions will just be noise. Most people interested now think they are going to get some amazing term like Chicago.RealEstate, Web.Site, Car.Insurance, etc. for cheap. It will not happen as the registries exist to make money and will be playing the role of domainer.
Secondary registries now are already racing to dump domains. .PW, .INFO, .CO, .ME, etc.
I think when the new gTLD come out there is going to be a race to the bottom. All the registries playing the role of domainer will be dumping assets in a fight to not get left holding the bag.
There will be a lot of registries looking for the greater fool, but there is only so much stupid money to go around.
It is also a double edged sword for the registries, because speculation might drive revenue but it also kills development. Without widespread development an extension will never have broad awareness or be a credible option.
This has killed many new extensions that have launched in the last 10+ years.
Brad