Not saying this is my perspective. TBH, a have mixed feelings on this one.
That being said, I do understand the line of thought that if one doesn't think Tua is "the guy", or has reached a limited ceiling, it isn't a matter of a "better alternative". There are no guarantees in any of it. They would rather go back to the draft and take their chances on great, that be stuck in mediocrity for another 7-10 years ala RT17, than commit a big multi-year contract, which will inevitably limit our cap flexibility down the line, to a QB whom they do not believe is the answer.
To put it more simply, I think they are of the opinion that "good enough" is the enemy of "great".
It makes sense if they are correct in their evaluation of Tua.