Interrupting other people to ask your question doesn't mean that you are engaging in collaborative coding. Collaborative coding in the sense you describe, doesn't really exist. What does exist is multiple people working on the same project, with their code communicating via interfaces, etc. Each person needs quiet focused time to do that.

The other issue you raised is that sure, your productivity may go up if you interrupt someone and get a question. It's clear that we don't want to optimize for that, because the interruption may cause someone else a loss of 30 minutes before they get back into the zone. It's not just 5 minutes. And 20 minutes into that recovery of concentration, someone else will interrupt them and ask another question. And they will also interrupt you. That creates a very frustrating experience. So it's better to ask your question asynchronously. You will get your answer when the person takes a break and relaxes their concentration. Both of you will be able to exercise control over when you can concentrate on getting your work done. Having that sense of control and ability to concentrate is critical to being productive.