It seems to me that actually, productive and predictable teams finish what they start. Going through the whole explanation, the base assumption is that tasks are clearly defined, there is few surprises, task pipelines seldom break in the middle because of external factors. Which is the hallmark of a predictable dev environment and by proxy, a productive team. All the team has to do to increase it output is stop doing…
Basically his reasoning is that overloading teams with more work than can be handled actually leads to delays and inefficiency. You get teams and developers waiting for each other and being blocked on each other. So, they start switching tasks and increase the amount of work in progress, which leads to even more blockage. It looks like everybody is super busy but it's actually very inefficient. Before you know it, you have lots of half finished things blocked on something and an issue tracker full of work that was specified months ago and probably is not even valid anymore. People get stressed and deadlines start slipping.
All this increases cycle times of individual work items. Reducing the amount of work in progress means things move faster through the system overall and less things get blocked. And when they get blocked, it gets resolved faster. Also people feel better about things because they get things done. And, they get feedback faster, which is also a good thing. The counter intuitive thing with this is that reducing the amount of work increases overall throughput and increases predictability.
I rewatch this once in a while because it is just such a great presentation: https://www.youtube.com/watch?v=L6v6W7jkwok&t=3601s
I try to manage my teams and products accordingly by creating clarity on what it exactly is that we are building from week to week and what the priorities are. I like having small teams or groups of people rather than having big teams. Because that allows me to have more than one thing being worked on. When it comes to product management, I don't like specifying too much ahead of time. There's no point in having months worth of inventory of feature work that won't get worked on until months later. By the time work starts, half of it is probably invalid anyway because requirements and priorities always change.