Right. You may recall that as she was lying down to sleep, she said, "The fire is dying"...Zampano then left her as she slept. Clearly symbolic. I see it as her will to persevere has been sapped
I think Il Matto was not killed, I mean, the beating didnt help, but because he had probably cancer.
Remember he told Gelsomina that he didn't had much time anyways. She asked what he means with that, and he avoided to answer him.
I think Zampano actually abbandoned her because he felt he was doing too much harm to her, and left hoping she will recover (that's why he left her the trumpet, her only joy while with him).
Eventually when he realized she died, he broke down in tears............still, remember he did this already with Gelsomina's older sister. Probably next day he went to buy another daughter to de old woman.
1. The fool did say why he thought he would die young: because of his dangerous profession as a tightrope walker. No matter how good he was, something could go wrong at any point.
2. When we hear about the first daughters death, Zampano seemed non plussed by it and just wanted to leave with Gelsomina as soon as possible. Then at the end of the movie when he hears about Gelsominas death, he is clearly distraught about it and cries openly. I think this clearly shows that he has been impacted by Gelsomina, more then by Rose, and he is at least that much changed. I personally don't think that he's just going to go back and buy another daughter, since it had been years that he left Gelsomina and he was doing his act alone at the end. (But I also don't think that he's now a totally changed person)
I think he probably had some terminal disease was already on the verge of death. After being on the receiving end of a beating from Zampano, he muttered that his watch was damaged or stopped working. A symbolic message that his time is up.