I get that being pedantic is fun and all, but give me a break.
If your salary reflects a 40-hr week, and you work 60, all you're doing is reducing the $/hr you make. If you do non-work-related stuff at work, and you expect compensation for it, you're billing your company for time you shouldn't be.
When you're salary your compensation isn't based on your time. So your argument doesn't really make sense. It doesn't matter how much time you spend on non-related stuff at work, as long as you get your work done. That's kind of the point of salary.
If you're doing your work in under the "expected" hours then you're basically making more $/hr. You can couch it in whatever terminology and pedantry you want--the work you do for the company is the only time in your work chair that counts.
No.. I think you're an consultant yourself and extrapolating your experience to the 9-to-5'ers. day jobbers can get their work done before lunch, but they're still stuck in their chair until 5 because that's the nature of a day job, and having a salary.
If they have nothing else to do and they're just sitting around then there's a systemic issue and the employee/employer relationship is broken in one or more of several ways, e.g., employer is over-staffed, employee is under-utilized, etc. An idle employee is a waste of money--e.g., they're effectively making more per hour and/or the employer is incapable of managing their resources, etc.
There's no extrapolation here. If you're idle at work then something is broken, and you're wasting the employer's money. If the employer is ok with the wasted money then it's all good, but the underlying economics haven't changed. If the employer isn't ok with this, or is unaware of this, then there's fraud.
... And I'm saying you're being pedantic, because the underlying economics are that they are. Workers are paid for output vs. time, whether or not it's shown that way on the record books.