In a general sense, I believe that people overestimate the cost of trading a package of draft picks.
Remember that many picks, including those in early rounds, go sour. (As we know all too well.) Indeed, out of a package of, say, 8 picks in a year, a team is doing pretty well if 2-3 pan out. That means that 5-6 of them are going to go away anyway. If a team drafts better than that they are beating the odds.
What really hurts a team is a sequence of years with reduced picks. In the NBA, the Nets traded YEARS of top picks to BOS for Pierce and Garnett. They are STILL languishing in jail because of that.
But we didn't do that for Goff. His direct cost in picks is already over. You could argue that we may not have had to trade for Sammy without the Goff trade, but that is not a first rounder, and it is only one pick,
Meanwhile, we have bolstered our roster during the year the draft cost hit the hardest. We APPEAR to have a stronger roster after the '17 off season than we had before it.
Did it cost us to get Goff? Yes. But to me, that cost was not that great. And we HAVE NOT mortgaged our future.
If Goff were to bust, it would hurt. But there would be no reason why we couldn't recover fairly quickly.