Tavares WAS the Isles while he was there, he was the driving only driving force they had, and he single handedly got them into the playoffs a few years.
if JT wasnt as important as he was, they wouldnt still be booing him every time he touches the puck. Its more than just the snub, his leaving took them from being an actual contender to being nothing more than a spoiler team if they get a lucky bounce.
They still havent recovered from his leaving.
If he had resigned, they would have been a contender, but without, they are maybe a playoff team.