If it takes over thirty years to clear a homicide case, that’s a failure by any reasonable standard.
This has very little to do with diligence and more with technology advancing.
And, while clearing murders is nice, wait until the equivalent RealPage gets hold of that database and starts discriminating based on your DNA.
Sometimes, there's just not enough available information to go on.
How would you solve the case if you knew there was a lady dead on the street, and then a few miles away there is an abandoned stolen car with a half smoked joint. No fingerprints.
Where do you go from there in 1989?
i mention this becaues the golden state killer was a police officer _and_ serial killer, and took advantage of the delay to kill over a great span of time.