Laporte was bought just after Van Dijk signed for Liverpool, but he did have a release clause which City had to go to.I'm not sure where you're going with this. Laporte was bought before the CB market went through the roof (because of what Liverpool paid for VVD). City have spent an absolute fortune on players including £40+ million on Mangala who left on a free transfer, over £50m on John Stones and just shy of £40m on Otamendi. This is all several years ago when those fees for centre halves were record deals. Then you look at their full backs and the various goalkeepers they have purchased.. hardly been a shining light of value for money and how to do good business. They just have unlimited funds and if you throw so much of it around you'll pick up a Laporte eventually.
A top team isn't made up for eleven "elite level talents" either. It's not how football works.
Your expectations are fanciful to be quite frank and it's no wonder you feel slightly irritated.