No I disagree with your assumption that 3 hours elapsed before finding the car. I have zero idea how long it took for law enforcement to respond to the 911 call. Other people have posted comments on this site that it took 2 hours. I'm pretty confident that LE didn't arrive instantaneously after the 911 call came in.
The point of my post was to delineate the events leading up to the discovery that MW was missing. That - to me at least - hasn't been very clear at all from the various reports, some of which are clearly inaccurate (like that he was seen in his car by hikers or seen hiking in the area). The Local has done some good reporting yet often lacks clarity.
The car was found 3 hours after the 911 call, we can agree on that. Actually, it was about 3.30a that the car was found according to SAR. The initial 911 call -according to an error-riddled account from the Local - appears to have reported screams in the area of Stunt and Schueren.
LE probably went out to the scene before deciding to call SAR. SAR says they were there 'early Saturday morning'. We've been told that FD and CHP also heard the cries but it's unclear where they were when they heard this.
MW's family says his last Snap puts him in the area at about 10 pm. If he was last seen in Simi at approx 9.30p, that's about how long it would take him to drive to the overlook. However, without knowing the content of the snap, it's also possible that he'd uploaded it earlier, the phone lost signal on the drive to Topanga (it's spotty) and then it uploaded when it hit sufficient signal. He would not have had to be in possession of his phone (which has not been found) for this to happen. It could have been in the car and then discarded by whoever had possession of his vehicle.
The cries for help were linked to the Stunt/Saddle Peak/Schueren area by witnesses and LE. Then a search ensued and the car was found. Then it was established that MW was missing.
It's unclear whether MW is missing from the Topanga area. The content of the Snap might be able to confirm that he was there - his family seems to indicate that it was the case and appear to be comfortable with the claim that he's missing from the overlook area.
The cries for help would have been taken to be a male voice for them to have been linked to MW's disappearance. However, when the cries were heard, MW's car hadn't been discovered so there were no details of identity attached to the search while the cries were heard.
SAR was out there relatively quickly and did some extensive searches is what is not the easiest search area. The canines losing his scent outside the car is puzzling, especially if the dogs were brought in early in the morning. Scent does burn off quickly when the sun goes up, especially in the summer but if MW was actually there (within hours) you'd think there'd be something.
I'm thinking out loud about all this because there are so many unknowns here, including where it is that MW is actually missing from or whether the Simi sighting have been confirmed.