"-What is a religion if not a big virtual reality game played by millions of people together?-" (some crap from that article).
Well, it definitely isn't that. Religion is a control system, a plug-in set of (random and/or fictional) answers to things people didn't understand about morality, science, death and the meaning of life (because there inherently isn't one except 'eat and breed').
By no reasonable definition is that a virtual reality game.
Religion also quickly fades where scientific understanding, health and resources flourish, and that's hopefully the world that will emerge from having robotics and AI do largely all the work needed for humans to get done.
As for an actual answer to what we do post-work... yes, I'm sure religion will remain seeing as nearly everyone is indoctrinated into some version or other at birth by their own family. But the main thing that people will do, IMO, an expansion of hobbies -since that's already what people do when they have actual free time and when they retire and choose to stop working jobs for money.
And that is essentially 'Arts and Recreation'.
I hope we'll see a transformation of our generic, cracked cement-covered, strip-malled, ugly cities become unique expressions of architecture and style (think the sort of buildings tourists travel to Europe and Japan just to look at).
Music and Games will expand. I just can't imagine how 'religion' would be considered one of those games, much-less one that becomes more popular than it is now.
People will move in and out of virtual and augmented reality at will. And, I think eventually when VR does become indistinguishable from 'true' reality, we will probably upload ourselves to a Matrix-like 'SimLife' existence -escaping all forms of danger and sickness we have to face right now (and the bounds of natural physics).
You could have a full customization life in a VR world. If processing speed increases, you could live a life of 'apparently' real time, but it could be vastly sped-up -allowing you to live hundreds or thousands of years in days or months.
I suggest people read 'The Singularity is Near'.