"You don't need metrics - just a suggestion box." Implied: managing the comforts for humans in an office is easy! (So easy that places like Facebook and Google have entire Experience Teams dedicated to it....)
In the real world it is always more complicated. There are always tradeoffs -- if you put in couches then maybe there's no room for quiet pods or a PlayStation or a lunch room or whatever. Always have on-going maintenance costs (who orders & pays for the fruit when the office admin is on holiday? Yet another thing to always remember and have to handover), and just the mind space required to deal with things. How do you know the office manager isn't picking the most expensive option every time? How do you know you're serving the vast majority who won't put something in the suggestion box? Etc.
Motivating someone to the near peak of their ability is generally the goal, but it's not easy... quite a bit harder than figuring out where to put the couch.
I'm a programmer at a manufacturing company and our offices all have (well we actually have two) canteens attached, Microwave, 4 rack toasters and a paninni maker.
Coffee/Tea/Water are available from a machine (you just put your token in and select what you want).
We don't have Sofa's but everything else we do have, I have a whiteboard behind my desk (though that is because what was a meeting room is now just my office).
Boss understands that staff comfort is important.
So no matter if your office has a personal sushi chef or just decent coffee, management's ability to empathize, see the pain, and compensate in some tangible way (not necessarily monetarily) can often be a huge motivator / confidence booster.
My boss insists I don't work over time (and if I need to do anything on a weekend I get the time back in lieu).
So while yeah they are basic perks I'll take no perks if I can have the above every day of the week.
For me as a programmer, 9-5 Mon to Friday every week, week in/week out is perfect - Work/Life balance is the best I've ever had since I moved to working as a programmer full time.
Everyone has standing desks and they are often used. Not all the time of course but most people use them occasionally.
Every company I've ever worked at has a microwave. Not having one would just be weird. Similarly every company I've worked at has whiteboards. They're cheap, why not have them?
My current company has fresh fruit and it all gets eaten. Just order less if it isn't getting eaten.
Anyway, I wasn't suggesting you immediately implement any suggestion an employee comes up with - you can survey your staff to see how many people agree. It's not difficult.