As someone who works at a company that has branches all over the world (including India) and employs people from all of the world, I've never seen this happen. Instead everyone who comes over on an H1B starts their green card application process as soon as they can, with the aim of staying in the US permanently.
Have slashdot commenters ranting about H1Bs ever actually worked at a tech company? Or tried to hire someone in tech recently? The idea that there is some huge untapped pool of US workers that are being ignored is simply bullshit - demand is so great currently (at least in Silicon valley) that its damn near impossible to hire anyone decent from anywhere.