Gronk was coming off an injury and started the first 3-4 games very slowly. He returned to form after that, had another tremendous regular season, and put together another fantastic postseason, despite missing a large portion of the AFCCG. Not to mention that Gronk is still a far better blocker than Kelce, making him much more of a nightmare matchup. Meanwhile, Kelce was nowhere to be found in the postseason once again.
It's not close.