What if the club is broke and can't really pay him?
The club
is broke. We're in debt, and until we get rid of it, everything we do is paid on a credit card. It would be incredible hypocrisy of the club to say they can't afford X or Y when they're spending 57 million on Neymar, 12 or whatever million on Messi's yearly wages, etc. - money they don't have in the first place. Besides, Valdes is leaving at the end of the season, surely not having to pay his wages will open up opportunities to lower the expenses and/or use that money elsewhere.
Either way, I can't really think of a reason why I would blame anyone but the club for the negotiations taking so long. Whatever it is that Iniesta and his agent demand, it's probably reasonable. But even if it wasn't, when it comes to players like Iniesta, who have been as good as he has been, and have given the club as much as he has, all you should do is say "Yes, sir. Is there anything else we can do for you?"