People underestimate the core of players Pep had at his disposal when he arrived. I get that some of these were approaching the end of their careers, but still: Kompany, Fernandinho, Toure, Silva, De Bryune, Silva, Sterling and Aguero is a very good core. Considering how mediocre his rivals were back then(2013 to 2017 was the dark era of the PL, imo), City really just needed to tweak the defense a bit before comfortably being the best team in the PL again.
Compare that to our core back then: DDG, Smalling, Blind, Shaw(post leg break), Herrera and just the raw potential of Rashford and Martial. Rooney was already way past it and Mata's decline was also evident.
It's safe to say that Pep never would have taken the job in the first place. And if he for some mad reason had accepted it, then he would have demanded way more money to be spent.