One thing that perhaps Americans always miss out or under rate in their own startup culture is the support ecosystem, especially the media

I see that in US, there is a media circle that continually builds itself around entrepreneurs and celebrates local innovation (like how TC began as such an idea), as the old ones grow bigger, younger ones come in and keep even the fringe entrepreneur in the lime light

In addition to the Tech industry you can also see this in the US sports industry. No other country perhaps has made sports such a successful business endeavor as in US. A great part of credit goes to its media.

Another big plus for US startups is 'local adoption', I consider this a huge advantage for all of them. Perhaps you have never felt it as you have never seen the other side of it. For e.g. you can never take it for granted in India, in fact being local startup has a good chance to work against you with customers. The positive news is that there is a sea of change in enterprises here, I have had recently a large corporation go for our product vs that of IBM/SAP. This alone can be a start of good times for Indian startups.