Some already have come back to teach (particularly in Distance Ed types of classes), but getting them out in the field for research is much less likely to happen.
Now, sure.  Wait until their pensions and investments are "Enronized."
Mine's not $ and its on Treasure Island far far far away in never never land, which is about as safe as I can get it for now, but I'm even thinking of exchanging that for a Gold Dinar account, but that would be too close to Iran just yet.
The other thing is that engineering in the US is not immune to GLOBALIZATION.  The jobs are moving to Romania, Hungary ....  Drawings are made in India during the night and transferred in the morning to project offices in the States.  Let's face it. Only the CEO/lawyers, tax accounts, law enforcement and lobyists will survive globalization.