Napoli was great this season but there is no guarantee that they will be great next season as well. There is a potential that they could be good, but there is a potential that they may not be that great at all as well. We should be careful about what's going to happen and if the transfer season starts and we get to see who leaves and who comes in, we can make a better prediction.
All of their players have someone going after them and that means a lot of money could be earned from the sales but that doesn't mean that they will end up doing anything important, it might be great or it might be hard but in the end we are not going to end up with anything good if they sell most of their players so they need to start focusing on who they can get instead.