1) May have once held sway in the minds of those who valued domains based upon type-in value metrics. With 1000s of new gTLDs not certain how type-ins will play. .Com still will be a default.
2) With 1000s of gTLDs .net may well get lost in the mix due to its lack of clear application.
3) I'm a fan of .Org so I'm biased. With that admission I'm a bit happy with the emergence of 1000s of gTLDs. I think .Org will hold its place in the minds of folks vs. .Net domains. .Net never gained mindshare at a "network related domain".
For "a nationality" a .Org makes a bit more sense, for a built site, vs. a .Net IHMO when it comes to building and sustaining a site + site identity.
... i've always believed the trouble with schools is that they teach absolutes .. they love formulas, this is worth that etc.
i think for a tech based website then net works and for most things org works, ultimately .com will always be king, i personally would never use anything unless i also had the .com ... unless the .com was already a strong site and i thought i could 'steal' some of their reputation by implication.
That's was the original reason for .org however it's been well and truly abused by some...I still prefer .net as a visual extension unfortunately the market/public perception favours .com however the caveat for that is it depends which country one is targetting.
I have some very successful sites running under .asia .co.uk .eu .in etc since they are targetted for those regions.