I can see Bobby as an interim boss, say if Tony was in jail or had gotten killed...but not really a long term solution for the family.

I think Bobby would've been eaten alive if he was boss. See the pressure Tony was under. And by all means, Tony was a semi good boss who made alot of mistakes but he held his own most of the time. I think Bobby would have been killed by his own men because of lost business and what not. Yeah he tried to persue money and respect when he was capo but the more experienced mobsters from NY would have raped him business wise.

It would never end well with Bobby being the boss, he wasn't for that life let alone for being a boss. He was better off with his train models.