I don't think any of your examples would have looked impressive just based on the idea. In all of those cases, the wild growth is what made the company a big story.
Tell the world that your startup will deliver burgers, and nobody will care. Then mention 1 million burgers served per day and you'll be a legend.
Agree with your comment. I think it's more a matter of startup fatigue.
Few startups seem that great without testing the product or seeing their growth. Dropbox? The idea is not so great, but the execution was just awesome. Google? (yet another search engine), eBay? (a place to buy and sell beanie babies), Facebook? etc...
Tell the world that your startup will deliver burgers, and nobody will care. Then mention 1 million burgers served per day and you'll be a legend.