Because he hit 18 goals for you last season..
Defoe is a tool, but he's possibly the best natural finisher at your club and for England, admittedly he goes for goal too many times when he should try passing but if he didn't shoot he wouldn't score (look at the Italy friendly).
Adebayor is a steal at about £5m, sure his salary will boost this to about £10m by the end of this year and then £20m by the end of his contract he scored goals for Arsenal, Manchester City and Tottenham last year, something he will continue to do.
I would however, have liked you to bring Damaio to premier league before one of the super rich clubs decide they'd like a new puppet to play with.