In economics, supply = demand. There's never a surplus. there's never a shortage. If you want more engineers, raise wages. They will come. If you don't want to raise wages, then you really didn't want them. Saying there's an engineering shortage is like saying there's a hamburger shortage because I don't want to pay more than 25 cents for a hamburger. If I pay $5, I could get a nice hamburger .and ... ta da ... end of "the great hamburger shortage" in this case.
Silicon Valley has the wealthiest people in the world and is a very expensive place to live. Engineering careers are quite short and living in an efficiency and washed up at 38 is not as inviting as our "we need more workers" mantra repeaters would have us beleive.
If they raise wages, they'll get what they want. Another alternative of those giant visionary West Coast capventure brains is use the principle of "capital mobility": just move the capital to where the labor is cheap. Not very hard, folks.