At least the indentured servants became both free and citizens after those seven years. These H1Bs are headed right back home with their dough once they’ve decided they’ve done enough.
To say nothing of their former employer's intellectual property. Yeah, foreign engineers and computer scientists may be cheap to employ, but they're very expensive once those folks take their knowledge home and sell it to your overseas competitors.
FWIW if you are in engineering or CS, get yourself a job that requires a clearance. Foreigners won't qualify for those positions (yet).
Or worst, report back to their motherland and teach their industries to compete against us, and upgrade their military to fight us. GOP embraced this and they wonder why they lost in 2006 and 2008. It will be a matter of time before the rank and file Dems will figure out that the DNC is doing the same, but more indirectly and behind the scenes. Third Party in 2012.