It's just a non-optimally worded sentence. He means people who came from Amazon, Boeing, Microsoft, and -- in addition to those people -- also people who come

It's just a non-optimally worded sentence. He means people who came from Amazon, Boeing, Microsoft, and -- in addition to those people -- also people who come from Seattle-area startups (such as https://www.rover.com/ https://www.rover.com/, to pick one at random).