Striking has historically been a significant problem on the Tube as well. That is partly because there is a limited supply of train drivers with the appropriate

Striking has historically been a significant problem on the Tube as well. That is partly because there is a limited supply of train drivers with the appropriate qualifications and if they strike then you can't just parachute someone untrained in to replace them. As you say, the risk of disruption to the travelling public from strikes might be reduced, though not eliminated, if the roles that still required human action had more limited responsibilities and required less skill/training. The DLR is a reasonable example of this in London, not immune to strike action, but historically less disrupted by it.