I think you're not giving the coach enough credit here.
You don't honestly think that when things are going good or great it's due to the players being good but when things take a turn for the worse, it's the manager's fault? Because that is how you could interpret that post.
No, but sometimes you have reasonable minimum expectations you want fulfilled, and when the said manager fulfills those minimum expectations and nothing more, then i would say that manager has done nothing special.
Juve with the squad they had, the minimum expectation was for them to get a top four place. Ranieri did just that, i wouldn't say he did anything special at Juve.
Looks like you didn't really follow serie A back in those days. 7 top players left Juventus and they weren't replaced. Chiellini wasn't even rated as a good player, even among the Juve fans. It was in Ranieri's Juve where he made his name.
You don't need to follow the Serie A to know that 7 of Juves players left. But Juve had a really strong squad then, that even after those 7 players left, Juve still had a squad that was more than capable of getting a top four position. They did not need a Capello or a Ferguson to qualify for the CL with the squad they had at the time.
As for Chiellini, i don't agree with you. Chiellini was regarded as a promising fullback at the time. At least thats how i rated him. Injuries to Juve's Centerbacks and Criscito's poor form forced Ranieri to play him as an emergency fullback and he just excelled from there.
After the best players left us, we had 5 stars (all of them, except Buffon, in their 30s already) and a bunch of newbies, who were supposed to fight against Milan (who won the CL only 3-4 months earlier) a much stronger Inter and a very strong Roma (Roma had a better team than us back then).
DP was in his thirties, but he was still a top player and was still one of the best in the Serie A at the time. Trezeguet was still a deadly striker and one of the best in Europe at the time too. Camo was still performing and was also one of the best(actually the best) wingers in the Serie A at the time. Nedved while not being as good as the other three, still wasn't really past it yet. Almiron and Tiago both came to Juve after having really good seasons with their club, Buffon was still the best keeper in the world. Zanetti was still playing really well and there were voices calling for him to be recalled to the Italian NT.
Roma did not have a better squad than you, that it just taking it too far. Compare them player by player, you will find that only their fullbacks and De Rossi would have made that Juve squad. Nobody else would have. Was Taddei better than Camo, was Mancini better than Nedved? Was Totti better than DP? Was Vucinic better than Trez? Doni and Buffon? Mexes and Chiellini?
You guys had a good squad that was more than capable of being in the top four, i would say it would have been a disaster had you not qualified for the CL at that season. It would have needed a Ciro Ferrara not to qualify.
Our defense was consisted of Chiellini-Andrade-Criscito-Zebina, but due to Andrade's and Zebina's injuries and Criscito's poor showings, the defense was completely changed. Most of those guys played for the first time in their lives together. In midfield we had 2 newbies (Tiago, Almiron and then Nocerino).
It was a group of players who hardly even knew each other. We started with a big disadvantage compared to Roma, Milan and Inter, who on top of it, had a better team than us. 4th place was the best every single Juve fan expected. Actually, the 4th place was something we dreamed of and secretely hoped we can get.
Ranieri ended 3rd.
I don't know how, but for some reason we all expected that. Maybe because we were aware that we lacked quality compared to the top 3 teams and because it was a new team that still had to gel.
Second season. They played CL last year too.
But this achievement in the CL will cost a lot. Even though Prandelli has the 4th best team in the league (4th or 5th, depending how you rate Roma's squad. Imo, Fiorentina have the 4th best team in the league) his team is sharing the 10/11th place in serie A. Fiorentina have one of the deepest squads in the league and playing Wednesday/Sunday shouldn't be a problem for them. But it looks like someone isn't doing his job right, with the preparations or with the squad rotation.
It was an achievement. In both seasons Milan and Inter had a much better team than Juve and in the first season Roma too had a (much) better team. In his second season Ranieri had to do with 6-7 injuries per round on average.
I mean, most of these guys you mentioned were old. It's like saying that Ferguson will underachieve if he gets the third place in EPL with a squad consisted of Giggs, Scholes, Neville and van der Sar.
Prandelli is not doing a good job this season, that much is obvious to everyone i would imagine. But you are downplaying his achievment in his first few years at Fiorentina imo.