Dick Dastardly cheats because... he's supposed to.All cars, crews, and drivers in the race have a gimmick. Otherwise, it wouldn't be wacky enough. It's in the rules. What's Dick's gimmick? Being the villain, of course. He's allowed to take shortcuts and set up traps because he's the bad guy. If he won without trying to sabotage others, then he would be disqualified for cheating.
Dick Dastardly cheats because... he's cursed.Basically, he and Muttley are immortal, as long as they don't play by the rules, he gets to keep living. But the curse also stipulates he will forever humiliate himself. He cheats out of fear that if he does not, he'll die, though this is more subconscious. That's why he's been alive since World War I and would have appeared in Wacky Races Forever.
Red Max is the son of the World War I era Dick Dastardly.He flies a WWI-era biplane which he has trouble getting off the ground, much less starting, much like the Vulture Squadron. He doesn't cheat, but he has used artillery to his advantage.
The universe itself hates Dick Dastardly.He was stopped for a speeding ticket at one point.
Dick Dastardly is Sweet Tooth's grandfather.My main basis for this theory is that both have a tendency to cause massive destruction in weaponized cars and their both villains, except Needles is more competent.
The Wacky Races are about as real as Professional Wrestling
Dick Dastardly cheats because... The Mean Machine can't maintain a winning pace.The Mean Machine seems to pass all the other divers multiple times during a race. Perhaps if it were to go that fast the whole race it would break down. So Dick stops to slow his opponents down so he can go at a pace at which the mean machine wont break down.
The Slag Brothers are from the same universe as The Flintstones and never appeared on that show.It makes sense because they're cavemen.
Dick Dastardly and Muttley are Time Lords, and the Mean Machine is their TARDIS.How else could they be in both WWI and the 1960's?
The races are a sort of reality showThe fourth wall breaks are done by people speaking into the cameras, cameras that are filming them race in a bizarre sporting event.
Dick Dastardly is a Ghost RiderAfter selling his soul to save his beloved companion Muttley, he's doomed to race for all eternity, with the promise that winning will set him free. The resurrected Muttlety was part of the faustian bargain, turns out the whole coming back to life thing turned him into sadist who delights in seeing his master fail. If he ever escaped from Hell, Dastardly would spend his life riding around the desert in the Mean Machine with a flaming skull for a head and Muttley as his skinless dog companion.