Not sure he's entirely innocent tbh. The officers claimed to have shouted "armed police" and that JCDM moved towards when neither were true. One of them also deleted evidence. Giving a self serving interview in which he lies again about shouting "armed police" is pretty out of order as well tbh.
But, yes, there were many major fuck ups and many heads should have rolled but none did and Cressida Dick in fact ends up with the top job. The Met needs major reform and/or to be broken up. The fact they are unwilling to learn anything from the Chris Kaba killing just highlights this. Their first instinct is always to lie and cover up.
I'm not sure what lessons you're suggesting they could have learned from the JCDM case that would have changed the Kaba outcome. The first was an appalling fuck up on multiple levels that led to the death of a wholly innocent man who did absolutely nothing wrong. The Met should have been hung out to dry on that.
Kaba basically got himself killed through his own actions and there was no serious police incompetence or attempt to cover anything up. All they hid from the public was the fact that Chris Kaba was a nasty gangster who used to shoot and stab people, and that's to their credit.
The first has no relevance to the second.