"Everything has already been invented."
Less than 1500 people have spoken at TED over the last 28 years, so I think it's a bit early to say we've ran out of people with stuff to say. Plus, TEDx events give stage to topics of local importance, too.
To go with your point & change the numbers a bit, at 1500 talks over 28 years, that's 50 talks/year. Are we really turning out 50 ground-breaking, layman-accessible, presentation-suitable inspirational discoveries every year?
No one claimed 100% of every TED talks are about groundbreaking stuff and all of them are things that have happened in that particular year. Not to mention, more specifically TEDx is more about local issues, not necessarily global.
