It's not.
Grealish - Jesus - Silva
Foden - Sterling - Mahrez
They can field either of those lineups or a mix and it'll just be one of their normal starting lineups. If Liverpool started Origi - Firmino - Minamino you'd question where the first XI was.
Liverpool I get, but in comparison to Chelsea and United who have an equal attacking depth, doesn't seem to help them. This is equally down to Pep and the way he utilize these players, the game time he gives them through rotation to build on their confidence.
Chelsea have Hakim, Hudson-Odoi, Werner, Lukaku, Pulisic, Kai (???) and United have Sancho, Ronaldo, Rashford, Cavani, Greenwood, Martial, they can equally put two starting forward lines like City...
Well it clearly isn’t a myth though is it.
They’ve played nearly the best part of 2 seasons without the best player in the league and it’s not even shown. £100m Grealish and world class Foden not needed for weeks and they are still destroying teams.
If City having depth is a myth, then we might as well all shut up shop and go home.
Foden is a youth product and credit to Pep in bring him to another level with his development, who is now benching players like Sterling and Grealish and with exceptional performance. Zinchenko also benches Cancelo and Walker, even right now Walker hasn't played the last 3 games it's been Zinchenko who's been part of the destructions City have been laying down.
City best XI would look like this
Sterling-KdB-Mahrez
Gundo-Rodri-B.Silva
Cancelo-Laporte-Dias-Walker
They're bench XI
Grealish-Jesus-Kayky (???)
Foden-Fernandinho-Palmer (???)
Zinchenko-Ake-Stones-???
Steffen
Even Klopp would struggle to finish in the top 4 with that bench XI. Pep has found players and developed them to play in multiple positions, Cancelo, can play on both sides as a fullback, Foden can play midfield, winger and false 9, KdB midfielder and false 9, B.Silva midfield, winger and false 9, Jesus striker and winger, etc.
The way I hear people going on about City depth is like it isn't Jesus but R9, it's not Foden, but prime Iniesta or it isn't Zinchenko, but prime Roberto Carlos, its not Stones/Ake, but Maldini coming off the bench for crying out loud.