I often go out of my way to fly AA and make PLT (and then some...I'll be at 77K this year), but the primary use for my miles is int'l upgrades. If this comes to pass, I'll fly enough miles to make GLD (for elite security lines, Group 1), but after that, I'll fly on price alone. Most likely, I'll start accumulating miles on UA again (PHL direct, SYD direct, more flights to ORD, IAD, etc).
Again, like most posters have asked, why not just raise the mileage req or do what FWAAA suggested? For some fares, the $500 "upgrade tax" is more than the fare itself...which I realize is AA's point (fares are super low), but again, there are other less abrasive options.