Your assertions regarding Goff are truth, but they have little to do with Donald. Assuming Goff is worthy, there’s nothing that says that the Rams can’t pay Goff and Donald in 4 years.
You seem to be assuming that paying Donald a huge contract now will somehow preclude them from building the team around Goff and paying him when that time comes. Nothing could be further from the truth.
Seattle realized early on that Wilson was the answer at QB and would eventually need to be paid huge sums. They still continued to have large contracts on the books on both sides of the ball while Wilson was in his inexpensive years. Once he got expensive, they had to part with some of those larger contracts. But in the meantime, they won a couple of Super Bowls!
It makes little sense to forgo a big contract extension for Donald now in the name of building around Goff when 1) Goff hasn’t proven he’s the answer at QB, and 2) he’s not due for a large contract for several more years.
Lastly, the impact at DT doesn’t have the limitations you think it has when the DT is leading the league in QB pressures for any position including DEs and 3-4 OLBs. I don’t believe Suh ever did that BTW.
You acknowledge Donald is HOF material. HOF performance transcends the normal rules of a positions value. The Pats have not traded one HOF player. It is NOT smart.