It's exactly this type of thinking that lead to the decline of Route 128 in the post-war years and the rise of Silicon Valley. If Google were to do this, they'd

It's exactly this type of thinking that lead to the decline of Route 128 in the post-war years and the rise of Silicon Valley. If Google were to do this, they'd be cutting off their nose to spite their face. They could not enforce such a contract with existing employees and all new employees would look at such a provision and join an employer who doesn't do this. The truth is that Google lost this market (or never really had it to begin with). At best they will end up like Microsoft, simply extracting rent via their patent licensing program. For more information about Route 128 vs Silicon Valley, I cannot recommend the book Regional Advantage by AnnaLee Saxenian enough. It's a bit dated and academic, but it's fascinating if you want to understand why the tech industry in and around Boston lost to Silicon Valley despite having a huge head start.