My thought for what it's worth (usually nothing but here goes)
The reason Jimmy hasn't signed isn't to do with money or playing so much but maybe more to do with where he plays when he does (This might of been covered in the thread, haven't been back to check)
For most of his career he's been seen as a winger/wide midfielder player even though he's some of his best form & games have come in centre midfield, certainly that's where he'd been playing for Villa when we signed him.
Maybe now he's turned 29 he thinks he might have to play centrally more often in the future to be effective as he was never the quickest anyway. While he will always be able to fill in when needed maybe he's looking for assurances that he will be classed a central midfield player going forward & that's not something we can give him?