He did but he also didn't particularly help matters in summers 2015 and 2016. 2015 he had a hand in De Bruyne and Sterling but no full backs signed and Otamendi came in who didn't solve the defensive problem. 2016 he came in and didn't sign a full back and Bravo was a disaster in goal.
It's always left Pep a year behind to where we need to be. We did good business this summer but are still short in midfield (Yaya kept around to fill a void when he's on his last legs), struggling at centre back without Kompany, a Mendy injury away from having no left back and have no other striker than Jesus or Aguero.
It'll be another year or two until the squad is complete and then Pep could be on his merry way. I don't see him here long term. I hope we at least have a season with Pep where we have a good full squad of players with hopefully 1 or 2 academy players.
I think the full back situation was a fairly unique one which maybe wasn't helped by the fact that Pellegrini knew he was pretty much just keeping the seat warm for Pep and so wasn't that interested in easing the path for someone else. All our full backs were over thirty when Pep arrived, three of them only had one season left on their contracts and the other one wasn't very good. I'm sure he (Pep) had to make a choice on which area he revamped first and he chose the attack, partly because it's the area that excites him most and partly because it was sensible financially to let Zaba's, Clichy's and Sagna's contracts run out and the release them.
As for Pep, I'll be surprised and majorly disappointed if he isn't around for at least another three seasons.