A rather simplistic posting, dare I say, bordering on the moronic.
Since when did City put out full strength sides in the FA Cup? Against Rotherham: Laporte, Fernandinho, and Bernardo on the bench. Jesus, Foden, Mahrez started.
Against Burnley: Sterling, Aguero, Laporte, Sane and Silva were on the bench. Mahrez, Otameni, Danilo and Jesus started.
Against Newport: Walker, Sterling, Gundogan, Laporte, De Bruyne, Bernardo all on the bench. Mahrez, Danilo, Otamendi, Foden, Jesus all started.
Against Swansea: Stirling and Aguero on the bench. Otamendi, Mahrez, Delph and Jesus started.
In the League Cup the rotation was more marked with the likes of Diaz and Garcia starting matches and Foden taking the lead role. Some of the appearances by De Bruyne have been attempts to bring him back after injury.
The defeat to Tottenham had bugger all to do with lack of rotation in the EFL Cup or the FA Cup and anyone who thinks so has not looked at the facts. Apart from anything else there were no Champions League matches during the intensive period for the FA Cup. The early rounds of the EFL Cup had no impact on the Champions League as City easily won their group.
Of course, City could have done a Liverpool and threw the EFL Cup and the FA Cup at the earliest opportunity and, likely as not ended up with no silverware.