I'd like to offer up a calibrator for some of our speculations. I posted this resource upthread, and it's so incredibly useful, here it is again:
https://crime-data-explorer.fr.cloud.gov
This is the FBI's "Crime Data Explorer". You can look at crime stats in Arizona as a good directional calibrator.
Some interesting points that surprisingly validate the notion of an abduction on the highway, and point out it's highly improbable a 72 year old man had anything to do with this disappearance:
Arizona
All violent crimes victims demographics
Location type - Residence home came in #1,
with Highway or Street #2
Victim’s relationship to the offender - Stranger #1 by far, and spouse came in far behind stranger at #5
About 80% of offenders are men,
Top three weapons used in crime: Personal weapons, Knife, Handgun
Offense linked to other offenses: 1)Destruction of property 2)Weapon law violation 3)Kidnapping /abduction
Homicide
Circumstances: 1) UUnknown 2)Arguments 3)Narcotics
Murder weapon 1)Handgun 2)Other firearms 3)Other - knives, etc.
Victim’s relationship to Perp: 1)UUnknown 2)Acquaintance 3)Stranger 4)Girlfriend 5)Wife
Perp - Age 70-79 - (Far less than 1.0% at 0.2380952380952381)
I encourage you to look through this FBI database on crime stats in Arizona.
Amateur opinion and speculation