The fiber isn't salvageable. Google did an "experimental" deployment which turned out to be utter trash. The short summary is they dug tiny little trenches in the road, and filled the gap above the fiber with foam. Vehicles, snow plows, and construction happened, which all happens to fairly efficiently rip the guts of their network out.
That's why Google is leaving: They don't want to redeploy the entire network from scratch.
On side streets I heard the quality of workmanship dropped even further, from micro-trenches with cabling a few inches below the road surface to cables that were barely covered and eventually becoming tripping hazards.
Possibly Caused by shoddy work by contractors as well - I have heard documented horror stories of contractors cutting the ends off telegraph poles to make emplacing new poles quicker.
That's why Google is leaving: They don't want to redeploy the entire network from scratch.