It has to start at the very top. Managers get bullied into creating multi-tasking cultures because they aren't allowed to staff projects sequentially. Every stake holder cares that their project is started, at the expense of when all projects will finish.

Early Paypal had singular focus, although I've only heard the stories told through the mythologizing of the founders: http://blog.idonethis.com/manager-focus-peter-thiel-paypal/

I think there's a way to manage remote teams that promotes single tasking. Because communication is harder with remote teams you have to make a choice: have more of it or have less of it. I always choose to have less communication by trying to simplify work, eliminate coordination (especially parallel projects), actually push decision making out to the edges. I don't know exactly how well the people who work with me enjoy it, but I know I only have one meeting on my calendar this week, and so I'm pretty free to single task at least.

Second this! I think we're seeing this change, at least in the tech space with notions like "Deep focus time" and "DND hours."