The post I quoted mentioned the Packers going 8-8 or worse if this trend continues which is why I mentioned the team collapsing.
Second, how is it that Brees, Brady and Manning can have terrific passing offenses with one highly paid receiving weapon (Graham, Gronk and Thomas, respectively) yet Rodgers for some reason needs to have two highly paid guys? The Broncos signed Emmanuel Sanders for $6m per year and I didn't see the Broncos passing game fall apart. Why is it so hard to see the Packers doing something similar? Sanders had 735 yards receiving in his final year with the Steelers and then exploded with the Broncos. In Oakland, Denarius Moore had 600+ yards receiving his first three years in the NFL before a disappointing season last year. Would it be astounding if Moore went from the quarterback play in Oakland to Green Bay and was, at the least, still a 600+ yard receiver? My money would actually be on him being a better receiver in Green Bay. In this example, if you're concerned that Moore doesn't play slot receiver then you can rest safe in the knowledge that Nelson is a REALLY good slot receiver (in 2013 he took 52.1% of his snaps in the slot)
Also, your stats on Cobb helping Nelson are great but the whole point of drafting a guy like Adams is that he'll turn into a good receiver as well. So why can't Adams help the team?
Finally, the Packers offense isn't the biggest problem with the Packers winning a Super Bowl, it's the defense. It's a matter of opinion but let's say that the Packers sign a player like Moore for $5m per year and Dan Williams for $6m per year (nose tackles don't get paid a ton of money, Kyle Williams is only at $6.75m per year). Basically you've spent $2m more per season and might get a slight drop in offense but a big bump on defense. Net, I think the overall team would improve in that situation. In my opinion, getting a good nose tackle and a slightly worse replacement receiver would put the Packers closer to winning a Super Blow than just signing Cobb and hoping Raji can re-discover the form he flashed five years ago. Packers-Seahawks might have gone differently if Lynch wasn't averaging 6.3 yards per carry. Combo of Adams and a Moore-like receiver could probable come close to the 69 combined receiving yards of Cobb and Adams in that game.
However, the above scenario assumes that the replacement WR will work out (though I don't think that's a large assumption with Rodgers at QB) and that Williams would maintain his level of play in Green Bay. So signing Cobb is probably safer but doesn't really fix any of the issues this team has on defense.