This is happening, as much as people on this forum (understandably) hate it.
I expect unmanned cargo flights within the decade (why do you think Airbus is pitching their A350F so aggressively.... they are likely selling it as a 1 person operation, with potential to be fully automated for the second half of its life)
Once it's clear those operations are perfectly safe, passenger traffic will follow suit.
It's been done on trains, it's been done on cars, it's been done on ships....