The Springbok players make it work
They're utilising a lot more players without being forced to and for a substantial amount of their games, the distances to travel are a lot shorter with far fewer time zones crossed.
I think RA absolutely needs to embrace selecting more overseas based players more often but they also need to understand what works in terms of number of players, which players and how frequently.
For instance I don't think it is viable long term for (let's say) Will Skelton to fly from France to Sydney on Sunday 4 August, train Tuesday/Thursday/Friday, play a test match on Saturday 10 August, train the next week then play on Saturday 17 August, fly back to France then a week later fly from France to Argentina, train Tuesday/Thursday/Friday, play a test Saturday etc.
Does that player fly back with a clear signal that they aren't playing that first test but will definitely play the second when they've had a better build up?
It definitely seems that the best way to deal with this is to utilise it across more players but less frequently on a per player basis than is possible so the travel, workload and disruption is managed.