I've generally observed that US rankings are more competitive than rankings in other countries, but that then leaves the question of why all of the top results in the US aren't also top results in India.
Google does consider host location, but, as aristotle suggests, Google looks at other factors as well. I would ask the same questions he asked... where are your backlinks from, and is there anything in your site that would suggest it's intended for an audience in India (or Ireland)? If the content is geo-neutral, then the backlinks might loom very large for this site.
I'd also ask is there anything about the terms you're targeting that might cause Google to localize them in some way?
We've got another discussion going on right now, taking a slightly different angle on the question you're asking, and that discussion is suggesting by implication that a .com is more geo-neutral than a regional TLD, which is one of the points you're making....
Optimising for global search consistency on regional TLDs
The discussion also cites a video by Matt Cutts that seems to support your feeling that a US server location should help rankings in the US, but, IMO, there's also plenty of room in the wording he uses to suggest other localization factors....
What impact does server location have on rankings?
Matt's conclusion, with my emphasis...