I am not arguing for bullshit metrics - I personally love working on things that may or may not pay off on a 10 year+ horizon and wish I could do more of that. But at the same time I've seen enough people coast to accept that most places that either isn't - or won't be seen as - tenable, at least not until/unless you've established a stellar track-record first.
Hell, I’d take that IT job. Keeping projectors working for a bunch of impatient creative types in exchange for getting to listen in on their presentations and earn their confidence enough to discuss their research as an interested peer while I repair their computers? Eating good food in a mess hall as I listen to quantum physics in one ear and mathematical networks in the other?! Onto the dream jobs list it goes, impossible as it might be in today’s academia.
Slack is important.
But so much so that you become a magnet for people who intend to do nothing, or somewhere where people who have fallen into doing nothing aren't noticed and dig their heels in and never leave quickly becomes a problem...
But if you're standing around because there isn't anything positive you can contribute at a given moment, that isn't "slacking off" to me. That isn't the problem.
The problem is if you create situations that effectively encouraged people to seek them out because slacking off won't get noticed.
I imagine scientific inspiration/insight comes in flashes. The ability to be honest in the job/what is going on/realistic is going to get much better results long term with better mental health, and trust making better internal dynamics.