How could you be as productive as an office of hardcore recruiters with their managers setting excellent KPIs and tracking goals and establishing milestones and shouting "a bit quiet over there!" occasionally?

By separating the performance of "productivity" (i.e. nearly everything you mentioned) from actual productivity.

Not everyone does well with remote work. For those that do, I wouldn't be surprised at all if they were nearly universally more productive...so long as the company is being serious about supporting it.