In my experience, virtual team success depends on experience.  I usually only hire people for virtual work who already have experience of virtual work — because I’ve been burned by too many “I’m sure I’d love it” newbies in the past.  Also, only experienced-in-their-craft teams tend to work well.  If you are strategically building an organization that will have significant future growth with high profit margins, you may decide to staff up with a bunch of cheap inexperienced workers who your fewer, experienced staff train and manage.  That business model, with a flock of cheap newbies surrounding each experienced expensive worker, pretty much requires in-house staff.