A counterpoint is Warren Buffett. His office doesn't have a phone or computer or anything that might interrupt him. He tells his secretary to hold everything while he goes inside, kicks back, and reads volume after volume of market data. To me, focus is more accessible to the wealthy. If I could afford it, I'd pay someone to handle Slack/phone/email for me so I could do what I most enjoy, which is get into a flow with the knowledge that I won't be interrupted.

It's true that the wealthy need discipline in order to achieve focus, but the poor need discipline and an environment that is conducive to focus. The latter is getting rarer and rarer. The very poor often live in crowded, noisy, and even unsafe areas.