Not only would the money cripple the Rams, now you want to take away the only cheap way to supplement the roster through draft picks?
Rams won't do that.
It's the same reason that RFAs only rarely change teams. It costs draft picks AND substantial money. In UFA, it's only money. In the draft it is just a pick (the money is small).
I could see Goff plus a budding player like D. Williams. Maybe even a 3rd round pick this year, even next ('cause the Rams are going to have several). But that's it.
There will be no blockbuster trade with the Rams that involves Goff plus given away 1st round picks.