I agree 100% with this.
There was a lot of this sort of thing mentioned in the series, but it was glossed over for the most part. The three biggest issues that stood out to me:
1. The fact it took so long for the LA jurisdictions to get on the same page that one dude was doing all this. The lead Hispanic detective (I can't recall his name) on the case was ridiculed for sharing this theory early on. This, I can sort of understand. He was a new detective, and very young for the roll. I can see other detectives telling him "Relax kid, not every murder is a serial killer"
2. The mismanagement of the first car and the prints on it was astounding. This is just incompetence. You've got a potential lead on a known serial killer and you do nothing?
3. The fact the surveillance was stopped on the dentist office was also astounding. Again, only real lead is the killer has horrible teeth. All the victims said this, dental records confirmed it. Another doctor said he'd need work soon cause of an impacted tooth. This is a guy that's killed several people and abducted kids (this is known at this point), and you don't have someone sitting in the dentist office...just in case he shows up?
The complete lack of cooperation of the various jurisdictions in LA was a sub-plot to the entire series, and it wasn't delved into enough. At the very least, there is a lot more there to tell the story of. I think that issue was the driving factor in all three of those issues above.
I wonder if Law Enforcement looks at those issues as training...sort of a case study.