Productivity is not the be-all end-all of a career! Human interaction (of any kind) is important, "wasting" time going to lunch with colleagues is important, serendipitous encounters at the coffee machine are important.
I know for certain if my employer decides to go permanent remote, I'll be looking for another employer. This is not the way I want to live and work.
If you've watched Red Dwarf, the entire reason that Rimmer was brought back as a hologram, was so that Dave would not go insane.
And another crew member could have been brought back, but Holly determined that Rimmer would be best. The conflict, you see, was required.
Many here decry the "waste of time" of being interrupted. Their attention divided. Yet you're indicating that after a few months of endless, day long shifts free of interruption, productivity has dropped a bit.
It appears for some, Holly was right. You need a Rimmer.
Also, long hours are not equal to productivity, and believing that they are is a quick route to burnout (which sucks, and you should try to avoid).
I think people need to realize that human interaction exists beyond the office.
Also, I think we should fully support what's suitable for people. I want to work remotely, but I want you to be able to work the way to prefer as well.