DIGI needed to run a cable across a street. So they sent ~6—8 workers to dig up both sides of the road.

If any other company did this (like Vivaqua), they would dig up the road, block it off and put up barriers, and leave. From there, they would typically not return for weeks, or even months, while everyone has to navigate around an unattended eye sore.

Why do they do this all over Brussels?

Answer: the instant they win a work contract, they are afraid the contract will be reneged on. So they dig things up immediately before the client can change their mind. So indeed, the reason so much of Brussels is dug up with no one working is due to job security fears. Or so I heard.. it may be conjecture.