Not buying players is not the same as buying badly. That's a mistake or an obfuscation of the truth which is often made on here.
When we purchased Otamendi and Mangala they were considered two of the most exciting centre halfs in Europe. The fact that with hindsight the Mangala transfer didn't work out is ... well, it happens. The point is you can't know when you go to buy whether you're buyhing poorly or not. What we didn't do in both instances is go for the "cheap" option. We went for the 'buzz' players. The kinds of transfers that are meant to be no brainers. But sometimes don't turn out that way.
Again this is factually incorrect. In the summer of 2012 we were not in a position to cherry pick the best player in football, nor were we in that position in 2014. No idea why you'd make such an assertion. In 2012 it was made crystal clear by the club's owners that the spending of the previous two years was over and that any significant additions to the squad would only happen if players were sold. In 2014 we were under sanction from UEFA so although both Pellegrini and the club wanted to sign Alexis Sanchez for example they also were cognisant that the priority position was centre half and a central midfielder was also needed.
Although there is some truth in what you're saying, it simply isn't as black and white as you're trying to make out. The overhaul of the team isn't happening "now". It started two years ago with KDB and Raz.