City lost all 4 squad full backs that summer and they were all well over 30. We replaced the 4 with 3 signings which isn't that profligate especially as I'm struggling to think of a full back we'd actually paid a big fee for since the takeover. Zabaleta cost £6.45m, Clichy £7m, Kolarov £16m and Sagna was a free.I was looking at it myself, the fullback position is the only place they can make that case but we needed to replace our fullbacks fast, with quality and experience of type that is in short supply.
This will be their sticking point despite all the above positions you mention and there will probably be comparisons to Liverpool because it suits their narrative. Liverpool got lucky though with their fullbacks. Robertson was a hopeful punt that paid off, Arnold is the first academy product they've had make the grade in years unless you count Sterling who only spent 2 years there before going pro. They also were allowed to ease them in from a position of no pressure, we had no such luxury after our first season under Pep, it needed rectifying fast.