Cousin signed a 3 yr 84m deal in March of 2018. It wasn't basically a 3 yr deal, it was a 3 year deal. This is a question, not an argument. You said that he was getting similar guarantees than other qbs, which I'm not arguing, but can you give specifics?
I said basically because he played a bunch of years under the tag and because he's signed multiple extensions since 2018. He did a 2 year extension at $66M, fully guaranteed, in March 2020, and he just did another 1 year, fully guaranteed extension, this offseason.
The point was to show that getting a fully guaranteed contract isn't earth shattering or ground breaking when its limited to 3 years (or less). It's not exactly risky from a franchise standpoint to do a 2-3 year guaranteed contract for a QB, when pretty much every franchise QB gets at least 2-3 years guaranteed on any contract.
When I look at Spotrac, it won't let me go back to 2018 without a premium membership, which obviously, I ain't paying for.
In 2019, Cousins was #2 in guaranteed money at signing, and #7 in practical guarantees. Goff, Wentz, Wilson, and Matt Ryan all had practical guarantees at the time of north of $100M, while Cousins was at $84M. Rodgers and Stafford were at 98 and 92M.
In 2020, when he signed an additional extension, he actually dropped all the way down to #13 in practical guaranteed money. Pretty much half the league at that point had signed a contract with more guaranteed money than him. Jimmy G, Alex Smith, Derek Carr, Tannehill, etc. Also was the year when Mahomes and Watson signed their mega deals. Had 6 QBs at over $100M in guaranteed money, 12 at over $70M
Like I understand when people say "Cousins started the trend", and they're not technically wrong. But the "trend" that Cousins started is very different than Watson's. Cousins basically looked around and said "OK, everybody is signing 4,5,6 year deals, with 2-3 years guaranteed. Why don't I just sign a 2-3 year deal that's fully guaranteed?". And the Vikings have obliged, likely because he's sort of that "fringe" franchise QB level and no team probably wants to give him the kind of commitment that others get.
Watson's contract basically has close to 3x the guaranteed money of the biggest contract Cousins signed, and its also fully guaranteed for five years. I could be wrong, but I've not seen any NFL team give 5 years of guarantees to any player.
Even Mahomes, who you would think would be the guy to get that deal, only got three years fully guaranteed at signing. Every other year is basically a series of roster bonuses.