Posted 05 November 2012 - 07:03 AM
I understand that Toni is more of an errand boy in LCS however he matures over the course of the game, but if you play III, you do realize he is a competent leader and strategist, as he basically is responsible for the destruction of the Triads in Liberty City, using Claude as the vector for their destruction. Toni lives with his mom mainly out of a sense of devotion to her, trying to care for his mother, even if she does think low of him.
The Triads are the Leone Family's most direct threat and their biggest enemy, and thanks to Toni and Claude, they are finished. They have no leader, as Claude killed the Three Warlords and dozens of their soldiers, their two biggest assets, the Fish Factory and the Laundromat are gone, as the Fish Factory is destroyed and the Laundromat is under Leone control. So, I highly doubt the Triads can wipe out the Leones as they clearly have the upper hand, even with Salvatore dead, the Triads are essentially on borrowed time.
As for the Cartel, you do bring up a good point in the fact that they have assets outside of Liberty City, but if you consider the fact that they've lost both their leaders and all of the major assets they had in Liberty City (such as the SPANK Boat, Panlantic Construction, Cochrane Dam, etc.) as well as dozens of soldiers and most of their SPANk supplies have been destroyed, the Cartel may be able to survive within the city as a severely weakened gang, but their glory days are over. They're at war with the city's two most powerful gangs: The Yakuza and The Leones, and are losing both wars. Their two main allies, the Triads and the Yardies are no longer useful, seeing as the Triads are essentially doomed and the Yardies are a minor gang.
The only other gang that could be a threat to the Leones is the Yakuza, but they are going through a succession crisis, and the only reason Asuka wanted Salvatore dead was to test Claude's loyalty, not out of any real desire to war with the Mafia.
The three hit squads are never really confirmed to be Leones or FBI, but either way, the Leones are significantly weakened, but are in no way doomed or defunct. Their biggest enemy is royally screwed, Toni is a competent leader, albeit nowhere near as effective as Salvatore Leone, and none of their assets and businesses were lost.
The only other gang near Mafia turf is the Diablos, and they are too weak and small-time to fight the Leones. The main reason they even tried to take the Red Light District in LCS was because they were being used by the Sicilian Mafia as hired muscle to harass the Leones. By 2001, the Diablos don't even have guns.
Yakuza don't like the Leones, but aren't seeking a direct war with them either. The Cartel could fight the Leones, but they are even more weakened than the significantly weakened Leones.
Toni is a decent leader, not great, but not bad either. And with the Triads essentially neutralized, the Leones could continue existing, at least controlling Saint Mark's, Red Light District, and Harwood.