"Only"? In comparison, Apple ships to a large number of nations simultaneously. I got my iPad shipped (from China, which is also where those Nexus 7s are coming from) the same day that US buyers got theirs shipped.
Such is how international companies usually operate.
I like Google the company, but they are incredibly provincial and out of step when it comes to these things. If they lack manpower to do international releases, perhaps they should hire the appropriate people instead of constantly treating the rest of the world as an afterthought.
Demand for these products is very high and producing them in large quantities while trying to keep them a surprise is difficult. If Apple, a company that is a hardware business has trouble with this it's hardly surprising Google a web software and advertising company would have problems.
Google constantly and egregiously fails to see a world beyond the US as being important to their initiatives. It took a ridiculously long time for customers outside of the US to buy apps on the Android Market (it remains seriously limited), and was significantly worse for those who want to sell on the market. With each of these hardware releases, it's the US and then, maybe some day, the rest of the world. That's Google's prerogative, and they're based on the US, but every time they do that they incrementally offend the rest of the world.
I disagree. I am a member of the rest of the world and I am not offended :)