Re: "not everyone is yet ready to return to the corporate altar"
"The object for employers is to come up with ways to evaluate productivity in a meaningful way."
It's a bit like evaluating a country's standard of living using GDP - it's not a particularly useful measure if you can't compare cost of living, free time, recreational space and possibilities, social bonding, educational, health, pensions, availability of food / clean water and air, and dozens of other things.... BUT it's relatively easy to calculate.
Same with productivity, it's difficult to work out a real measure of productivity for a specific job, and practically impossible to compare productivity across people in different jobs (even similar ones, and even ones with the same job title where responsibilities are a bit different). But, hey, time spent at desk / in office / logged in is easy to calculate so let's go with that.
It's exactly the same as looking for your lost keys under the streetlight because there's light there, even though you dropped them somewhere else.