He signed a new contract and would have better offers than us anyway now
If Balotelli carries on playing like that, the goals will come hopefully. We won't play against many teams who let him play on the shoulder and find space in the box so easily, at least not without putting ourselves into a position where they switch off because we've already lost.
I like Balotelli and hope he stays in English football mostly because he's a character, especially when he's on form. That said, I don't think he'll come good for Liverpool, the fans and the press are against him now and I think his ego will make him more likely to fuck off than knuckle down.
Falcao is in a similar position at United but he has a far tougher job or coming back from injury and having to compete with Rooney/RVP for a place. These excuses will let him see out the season in the hope that he finds form. I'm not sure if he will though, especially when he's playing for scraps at the moment.
Ultimately I think they were both poor transfers. Falcao's screamed of "we're Manchester United we're still relevant to attract the biggest names in football" despite not actually needing while Balotelli's was more "oh shit we just lost a big name striker, we need someone else well known so we don't look like a selling club".