It took years for Luciano Spalleti to achieve the fantastic results for Napoli, and lifting the scudetto with Napoli after 33 years without a domestic title was a very memorable occasion for them. Luciano Spalleti resigned from his role as Napoli's head coach, but he did so for personal reasons.
You can say it about Napoli and their President De Sanctis as they spent about last twenty years to build up their club after ranking up from Serie B. From Lavezzi, Hamsik, Higuain, Cavani, Insigne, Koulibaly, etc. and they only won a first Scudetto after many decades in the past season.
You can not say it with their coach Luciano Spaletti because he
just joined Napoli since 2021 - 2022 season. He only had two seasons with Napoli and in a second season with them, he won a Scudetto which is a first one in his coach career too.
When it comes to the incoming boss, Rudi Garcia, he will undoubtedly fall short of the outgoing manager's expectations. However, I believe that if Rudi Garcia is given more time than Luciano Spalleti, he will make good use of his position and provide solid results for the club and the supporters.
Will Rudi Garcia repeat the success of Spalleti?
I am not sure but he had some good seasons with AS Roma in the past and from their coach record, they have kind of similarities.