Willy should get a new deal. No chance of the other five staying. Of those five, Sagna would be the one most deserving of another year, but only as a backup. There are good players coming through in some of these positions now. There are four players at U16 or U18 level who are as good as Navas (Sancho, Brahim, Foden, Poveda). The first of those is physically ready. The other may be a while off, but there has to be clear routes through or there’s no point having a great academy.
Main reason, or second to underperformance, is contract ammortisation, though. City could replace most of these players with £30m/£40m younger alternatives and actually improve the books given the high salaries some of them are on. Those five - Toure, Navas, Zabaleta, Sagna and Clichy - must all be on anywhere between £75k and £200k (Toure) a week.