.Web is the most likely TLD to do well and be a permanent fixture. Everyone calls the internet the 'web', it's more inherent that any site should be a .web, .website is just too long.
Have you seen some of these awful extensions, .party .red .ski. This is just a money making scheme for the internet overlords.
As far as devaluing the current C,N,O,B,I main TLD's I can only see the new TLD's making them stronger because of one value that just can't be modified, bought, or back-linked; DOMAIN AGE.
.COM is king and always will be.
I have seen a huge increase in .info domains in demand lately and people aren't picking up org's or net's just because they aren't sure of the market. Which I think is a bit absurd, because there are plenty of them out there with a 9 year + domain age.
Unless google decides to not use domain age as a metric for page placement, aged exact match .ORG and .NET domains should still maintain a place in your portfolio.
Yes, content is always extremely important; but if you measure two domains against each other with the same metrics the one that has the greater domain age will always rank above the other.