A player who graduates from a midtable PL club to one of the top four or five knows he'll be expected to work for his bread, and if he comes to Arsenal he knows it's to a club where his technical level will not be his outstanding quality.
Chamakh, who I still like, came to us on the back of a good, but not scintillating season for a club that wouldn't make the CL places in England. Talent wise he's a cut above mediocre: movement good to very good, touch good, finishing average, and he notionally has qualities that complement our other forwards, like being strong in the air.
Chamakh has a good work rate when he's fit and well, although he has had trouble adapting to the continual physical intensity of the PL.
Aside from the fact he came on a free, which was nice of course, ask yourself why he's an acceptable signing but our current example Doyle isn't? Why are we scouting Ligue 1 but not the Prem?