I want to agree with sentiments like this because they serve my interests, and maybe I’m just lazy, but with loose deadlines and minimal pressure I’m just going to be messing around and not “thinking openly about solutions”
What I argue for is that during normal, daily, non-emergency work hours your employees should not run at or over capacity but with a headroom. And if you want them to solve a long-standing, complex problem and you want them to solve it well, you have to give them the resources (e.g. time, mindspace) to do just that. Sometimes this just means: "Steve, on Fridays you don't have to answer any emails and phone calls, or do any other thing, just focus on finding a good solution to $PROBLEM").
In my experience that yields better solutions and doesn't take much longer (quite often the opposite).