The real reason Dell moved corporate support back to the US was because they have run out of the engineering talent pool they have so proudly talked about using. This talent is moving quickly to non-voice BPO work with companies such as IBM, MicroSoft, Oracle, Accenture, etc. They have been using liberal arts grads, undergrads, etc. Computer support is difficult without the background. We've seen this before.
Dell's follow-up announcement the day after stating they were committed to India was to quell investor concerns. As stated elsewhere, investors only care about one thing.
Lehman Brothers cancellation of their in-house support required knowledge base with Sybase, something WiPro and TCS couldn't meet in the end.
Indians are good at this - staying on top of the "hot" technologies. I don't think that the expertise (that comes with years of experience) exists there yet.
BTW - Some companies are touting US support for all customers. MPC (formally Micron) made such an announcement recently. They took a jab right at Dell stating their top support is not just reserved to corporate customers.