The Rams cap hit for Goff in '17, '18, and '19: $6.3M, $7.6M, $8.9M
Compare that to the Seahawks hit for Wilson the same three years: $18.8M, $21.7M, $23.2M
... or to the Colt's cost for Luck: $19.4M, $24.4M, $27.5M.
Over the next 3 years the Rams will pay their QBs $40M to $50M less than SEA and IND. I just used those 2 as an example but could just as easily have used Brees or Flacco or Rogers or Roethlisberger or Manning or Rivers or Newton or Ryan or Brady or Tannehill .... well, you get the picture. (Did Tannehill surprise you on the list? His cap hit over the next 4 years is over $80M!).
Hopefully Goff earns one of those mega deals starting with the 2021 season, but in the mean time the Rams have money to work with. If they choose they could sign a FA to a 3 or 4 year contract that would fill the gap caused by trading that #1 pick away and still have money left over to take care of other priorities.
AlbaNY_Ram