I've been following the progress of a plaster monolith about three feet high that appeared South of Market over a month ago. (Not to be confused with the bookcase monolith documented here.)
Also, our civilization failed to evolve.
Far as I can tell, that is.
The thirds sat there for a long time.
The remaining section is getting a little mashed on one side. Maybe soon bits of it will fall apart enough to be swept up. Or washed away if it ever rains. Some chance the chips could even be fed to a street tree as extra calcium. Environmentally speaking, that would beat lugging the whole original monolith out to the landfill as a lump.
Not sure I would call this a case of the street finding its own uses for things, as William Gibson likes to say. It's more like the street (this SoMa street, anyway) digests things. The way bugs and rot work on a dead birch log until all that's left is a cylinder of bark. Humification. A while ago Folsom Street went to work on a dead vacuum cleaner: the metal parts were gone in a day. The process works pretty well on most things. The monolith is a tough one -- it's taking longer than most.
Except now there's a tire.