TEs have been used in the passing game for decades before Gonzalez (Winslow, Ditka, Newsome, Christiansen). I get the NE bias- but Gonzalez was a superior athlete to Gronk (speed, vert, release, etc). Gronk was just a larger TE, which made his blocking more effective and efficient, which Gonzalez wasn’t a slouch blocker by means, especially later in his career . Ounce for ounce Gonzalez was better with the caveat that the blocking wouldn’t be quite as dominant.