What I've seen is that the competitor buys the excavator and the 15 people have to do the work for similar pay. The salaries go down, amount of work per worker

What I've seen is that the competitor buys the excavator and the 15 people have to do the work for similar pay. The salaries go down, amount of work per worker goes up and the competitor makes exotic profits. I've seen one fascinating example where pay per unit eventually boiled down to 40 cents per hour. That was the point where the automatons simply could no longer keep up. Some would decline to do the manual work. Those who did got the less frequent better paid contracts that paid up to 20 euro per hour. (for which no machine exists)