They can't really, because they've burnt their boats by cutting themselves off from their roots in Albino and Leffe, where two new clubs, bearing the old clubs' names, have been formed. So, with their boats well and truly scuppered, they have to either swim or sink on their own!
You're right that it was a bit of a shotgun marriage, as the two towns and the supporters of their respective clubs didn't get on well. It was a bit like what happened in Inverness, except that there the team remains in the city, whereas AlbinoLeffe has become the second team of Bergamo. And so far the Inverness merger has succeeded beyond anyone's wildest dreams, and presumably silenced even the most fervent doubters.
AlbinoLeffe made a serious tactical mistake when Atalanta fell into Serie B in 2010-2011. Instead of offering cut-price season tickets, as Atalanta did, they increased their prices and saw their season-ticket holders more than halve from 2,500 to 1,200. And this just when it seemed that they had found a niche and were beginning to create a fanbase of respectable proportions.
It's been more or leaa sll downhill since then, and I will not be surprised if crowds are in three figures for many games in the coming season.
In the Serie B days I several times came across little groups over from England for a football weekend at their games.