Actually, we wouldn't have had to. Reports were we were looking at giving Campbell 10 per year, right? If you give 4 of Gresham's to Campbell (14 per is what he got) you have on of the best DE in football locked up and considering how much of a waste of space Gresham is (and WAS back then), you can't tell me you couldn't replace his production or lack thereof with 3 million bucks, or if need be, find another million bucks to free up to get one of those guys you mentioned above.
I don't know how people are arguing this whether they made the call or not back in the day. The Jags had enough foresight to see how valuable Campbell would be, the Cardinals didn't and instead spent big money on a guy who produced next to nothing but headaches from stupid personal foul penalties at a position that wasn't even valued in Arians' system.