So, What's the Problem?
The criminals are all super-geniuses, and not one of them can make an honest living.
Almost every locale in the Scooby-Doo universe looks like the economy has just taken a nosedive. Even their nice "vacation" spots look like bad neighborhoods in Detroit.
"Gee, Scoob, it sure is spooOOOooky how many out of work mechanics this scene implies."
In the 25 episodes of the original Scooby Doo, Where Are You? cartoon, our gang comes across four deserted mansions, two abandoned castles and an empty ski resort, amusement park, ghost town, mine, Hawaiian village, airfield and mill. And of the 27 villains the gang encounters, 23 are motivated by monetary gain via theft, smuggling or land speculation. The Mystery Machine crew isn't running into domestic disputes or drug-related crimes. They are dealing exclusively with people who need money so badly that they voluntarily squat in the basements of abandoned houses for the off-chance of landing a paycheck. And if the villains don't need money, they need work. The remaining four motives? Winning a dog show, getting an acting gig, revenge for getting fired and a hatred of robots. Those who don't need money or work are acting out of a hatred for robots, the quintessential job stealer.
"Beep bop boop. No, I'm not union, why do you ask? Bop boop beep."