Unqualified: One of the questions they asked me was the difference between a TCP and a UDP packet. I assume this question tripped up earlier applicants.

Foreign: On their ad, they specified that they couldn't sponsor H1-B Visas, because they had a lot of replies asking for that. They didn't want to deal with a language barrier.

Unmotivated: I learned after I took the job that of those applicants that weren't A or B, the rest of them really wanted to work in games. They decided against hiring them because they were worried about the guy jumping ship as soon as a game job opened up.

I was the first guy they interviewed that didn't have any of these hangups, and jumped immediately on me, despite having no real previous experience with C#, .NET or other C-like languages. They offered me the top-end of my salary request range. I had nothing to negotiate. I can't imagine this having happened in anything other than a seller's market.

Companies unwilling to do H1B visa sponsorship probably are not refraining due to language barrier issues. There is a cost, both money and time involved that small shops simply can't afford.