If Cowboys fans want to call him the GOAT I won’t argue too strenuously. But I do wonder if there’s a single person outside of Cowboys Nation that would do so.
Anyway, he’s an all-time great even if calling him the GOAT may overstate things.
There's no question that most would call Tony Gonzalez the GOAT, and with good reason. There's no TE that holds a candle to Gonzalez as a receiver (Gates, Sharpe and perhaps others matched him at their peak but weren't as good for nearly as long).
Often, you'll hear announcers or others talk about Witten as the best "all-around" TE, and certainly he's been more of a blocker throughout his career than Gonzalez or, say, Gates or Sharpe, ever were (yes, he's been slipping lately). But it's a bit like saying Willie Mays was a better all-around player than Babe Ruth or Ted Williams: it's true that he was a much better fielder and baserunner than those guys, but Ruth and Williams were SO much better as hitters that it more than made up for those other things. Sometimes one dimension is all you need if that one dimension is good enough.
I'd probably stick with Gonzalez as #1 to Witten's clear #2, but it's awfully close.
(If Gronk can ever get over his health issues, he could easily force himself into the conversation, or just take it over.)