It's honestly quite impressive that it took them this long to do this.
> The operation took place between March and August of this year, it said.
You can also ask why they move it to London and not mainland Europe.
These systems AIUI have huge amounts of inertia, by design.
Italy is the third country with the largest gold reserves since the 50s or so, and most of their gold is in the US.
The idea of repatriating it comes up from time to time, but the truth is that it's s logistical and diplomatic trouble with little positive outcomes.