Taking over five years to design and manufacture along with $100 million, the Krupp Digging Machine is the largest trenching machine in the world. This amazing machine is 700 ft long and weighs over 45,000 tons. Take a look at more of the world's largest machines at Oddee: Link
In this case the bigger machine is actually more efficient that using lots of smaller ones.
Also, if you want, there are still parts of this world where you can live as a hunter gatherer. Not really nice places, though.