When City bought Dzeko, Toure, Silva etc, clubs were only asking for 30m, 40m max. And you get the occasional "Abramovich-craze" where 50m was spent on Torres.
With the uprising of richer clubs - PSG, Monaco - the price only continues to inflate. The money spent on Falcao only served to inflate Cavani's price, or any player of his stature. Now clubs are asking 50/60m.
Obviously City is rich enough to compete, but undeniably, City is crippled by the FFP rules. It really is a wonder why it doesn't seem to affect Monaco.