That's a dangerous and reductive line of thinking. There are plenty of factors that can lead people to believe (correctly or no) that they don't have leverage i

That's a dangerous and reductive line of thinking. There are plenty of factors that can lead people to believe (correctly or no) that they don't have leverage in an employment negotiation. First job out of school, first job in the tech industry, family causing them to want to stay in an area without many other prospects, etc; NDAs are an employers way of leaning hard on the fact you need them a lot more than they need you.