Hard to say at this point.
I think we all need to remember that its not simply about getting A QB. Its about getting THE QB, and with a pick that high, he better be very good. By just about anybodies standards, this isn't a great class for QBs, and if teams aren't in love with these guys, trading up to get them doesn't make a ton of sense.
Knowing Chip Kelly, who knows if the 49ers are even interested. If he wants to run his stereotypical offense, one would suspect that Kaepernick would be a better fit than Wentz or Goff.
Obviously, QBs tend to come off the board sooner than expected historically, so in all likelihood something like this could happen.
The other key thing to look at is draft positioning...
Lets say no QB goes in the top 5, and we get to us at #6...who's coming up? After SF, the next logical choice would be Philly at 13 and the Rams at 15. To me, Philly makes very little sense, because they just invested $18M in Bradford and another $7M in Chase Daniels this offseason. So how realistic of an option are they?
So you have the Rams at 15, the Jets at 20 (I don't see Buffalo at 19 moving up), and Denver at 31. That's about it from what I see.
So in my opinion, three teams that would even be remotely interested in moving up to 6 to get ahead of SF. But what if a team has Wentz and Goff as equals? Meaning if the 49ers take one of them, the Rams don't have to trade up to get the other one, because they will fall right to them.
Not to mention the gigantic cost it would take for a team to move from the teens or even as late as Denver to get up to 6 to take a QB... and this is a bad QB class.
Bottom line... I don't see it. I think the Browns take Wentz, and then MAYBE somebody moves up for Goff. Other than that, I think Goff slides all the way down to the Philly/Rams range before getting snagged.
First off, to question if anything Philly would does is realistic is funny to me. Right now, it seems that they have a higher turnover rate than McDonald's, so you really never know where they are going. I definitely think you mentioned the 3 teams lower in the draft that need a QB the most, but you never know how things are going to pan out. An aging Brees in NO, an injured Cutler in Chicago, Tannehill in a system that isn't really suited for his skill set. There are still a great amount of possibilities left in this draft. Everybody screams they don't want a QB until a solid prospect starts falling down the board. If it happens, I think teams will scramble.