Again, if not Dak, what? $35 mil this year won't be "elite" money before his new contract would run out, just look at the top quarterback salary history. Have to also look at the long term, maybe he's not "worth" $35 million a year now, but even at his present level in a couple of years guys like Mahomes, Jackson, etc. will be at the $40 or more million level, do the franchise thing with Dak and the cost will just go up and up. Lock him in now, and even if he doesn't improve, his cost will be in line with his "value" before the contract runs out (and teams can do contracts so that they can get out of it before it's over), and you'll know what you have tied up in Dak so you can budget your cap for guys like LVE, etc.
I understand, I'd also like another Roger or Troy, or a Mahomes (he hasn't won anything yet, by the way), but it's a bird in the hand question, if you want to roll the dice and hope you can trade for an aging Rodgers or such, and he'll still be productive (witness Montana after he left San Fran, e.g.) or trade away tons of high draft picks to get - keep your fingers crossed - a top rookie who won't turn out to be another Russell or Winston or such.
There's no cut and dried answer, it all depends on your desired course of action....