How can 5 at the back have an issue of width? Short answer: no, the exact opposite. It's also the formation Mourinho used to good effect to nullify 4-3-3 formations of City/Liverpool.
It's more about tactics and quality. If your wingbacks spend all their time attacking, don't pay attention and don't track the fullbacks very well, you can get outnumbered. If they play how they're supposed to, you don't. If one team has a very well functioning attack and the other has dysfunctional, sub-par defence, it's easy to blame it on the formation instead. People forget Liverpool have been tearing defences to shreds at Anfield, they have 17w and 1d. Chelsea were always unlikely to come away with anything there, whichever way they set up.