Sure, but you have to start somewhere. Why waste money digging up the same street over and over, as most cities do? It seems more efficient to do it once and be done for a long time thereafter.
At least you're getting something back. When the channel between Dover and Calais was bored, one of the boring machines was simply left underground, because it would have been to expensive to retrieve it.
... cut up the boring machine for scrap!
It's like setting up a giant printing press to print a newspaper, and then printing 10 copies.