Large corporations have this sort of structure where you're a node in a graph performing a niche service(s) in a series of steps where there are dependencies and you are also a dependency for later stage services. Working every second of the day and working really hard, doesn't actually do anything since you're just one cell in a slime mold. Rather, you wait for another node to deliver some sort of task, do your part…
But in a team setting, the goal is some external output that depends primarily on efficient collaboration. Individual capabilities still matter, but it's how they are applied in concert that delivers results. From this perspective, pacing the team isn't necessarily about preventing burnout, but more that it hits diminishing returns pretty quickly, and becomes counter-productive when the team gets stretched too thin to react to new inputs that inevitably come.