Perhaps my perspective is skewed by working mainly in the office in a massive corporation and that a lot of these 'time wasters' are something that seem like an outcome of the environment: you need meetings to make sure you don't step on each other's toes (and there are many toes around), the pipelines take a long while because there's a lot of code that needs to be built, chatting with colleagues happens because sometimes the requirements are not entirely clear. In this utopia where there are no such external factors, I think a consistent four hour focused work day is feasible. But it does seem too idealistic.