Garcia needs more time to stabilize the team. Garcia did not get a chance to build the squad to his liking. I'd say Garcia, given enough time and opportunities, can bring stability to Napoli's performance. However, Napoli are not favorites for this season's title.
I somewhat agree with you. Napoli's performance is slightly weaker than last season. But their performance is very weak? I don't think so. Napoli have lost only two matches out of 8 matches. Although they lost against Madrid in the Champions League match, they won the match 3–2. Not too many poor performances from Napoli. And so changing coaches cannot be a solution now. No one can guarantee that Napoli's performance will not deteriorate further if a new coach is appointed. That's why I think the Napoli management should trust Garcia. And he should be given more opportunities. It would not be the right decision to change coaches so quickly.