One of my father's friends did maintenance on large bucket wheel excavators in the GDR. He told how they added sensors and electronics in the late 80s until the

One of my father's friends did maintenance on large bucket wheel excavators in the GDR. He told how they added sensors and electronics in the late 80s until the electronics failed as often as it helped, so humans remained indispensable -- if only to tell false positives from actual defects. There seemed a clear point of marginal utility in automation.