You need to do this anyway, current infrastructure does not last forever. Electric lines, gas lines, optic cables, sewage systems, everything has a lifespan and at the end of the lifespan you either exchange it or risk cascading failures. At that moment, adding capacity for new construction is not a huge extra cost, especially if the density is high enough.

BTW, utility tunnel is a thing, and places like SF can probably afford some, to prevent disruptions to the surface.

https://en.wikipedia.org/wiki/Utility_tunnel

We have about 90 km of utility tunnels in Prague, with a plan to expand the network to 120 km. Really helps in the historic centre.