Amazon’s planned $3.9 billion acquisition of One Medical will bring Amazon further into healthcare. But whether the Seattle tech giant will upend the medical system in the same way the company has changed how people buy products online is an open question. “It’s a shot across the bow of the whole industry,” said startup veteran Mike McSherry, CEO of Seattle digital health company Xealth. Amazon has been edging into healthcare for years. In 2018 the company bought PillPack, which became Amazon Pharmacy. And it recently expanded Amazon Care, its primary care service initially designed for employees.