Childish behaviour to think Otamendi or no Otamendi is the reason we do not have a CL and several other trophies. You can't be so naive to pretend everything can go perfectly. Took Liverpool 30 years and world record fee for a centre back, keeper, and several other signings to get it right and win a league title with Klopp. We managed 4 in the last decade, if anything, we were spoiled. There's obviously things we can do better and criticize, like I have heavily criticised Pep for Lyon and Spurs loss in CL, but I don't think transfer strategy is one that warrants it as much, if this was a left back debate I'd still be inclined to feel it's not been addressed that well, but there's so many factors.
City bought those defenders carrying big reputations at the time, it isn't their fault they turned out shite. Otamendi before City was in la liga's team of the season and immensely highly rated, same with Mangala. While the latter couldn't last at least Otamendi showed fight and had a great 17/18 season. Way too easy to sit and rant, I'm sure the club higher ups feel they can do better every season as well, along with our players and manager.