It took me a few years to add one city, I was always told it wasn’t high on the list of priorities as it requires some dev time apparently.
Eventually it got done as our country was going to get States added, so they asked for a list of cities where we wanted to setup a metro, and they used the same dev time for it as when they were setting up States, that was in 2017 after asking Liz and then Daliah.
We haven’t needed to add more since, so I don’t know about now. Just expect that it won’t be quick, but keep asking.