I think that Cobra-La would have worked better if it was called something else, and if it wasn't connected to Cobra. The used car salesman origin for Cobra Commander isn't much better, but I think that Cobra works better as a ruthless terrorist organization than it does as an ancient conspiracy.
Seriously, there was an alternate origin where CC had been a prior used car salesman?!
The comics.
Frankly if some nobody in the middle east can whip people into a frenzy to the point where they are blowing up sky-scrapers and attacking Government buildings in the USA and masterminding terrorist attacks around the world then a used car salesman isn't that much of a stretch.
Frankly if you own a used-car-lot you already know how to contact people to get stuff... Cars... parts... repairmen... You know where to order stuff how to organize people...
It's not that much of a stretch that this business-savvy-but-down-on-the-world dude decides to buy an ex-military vehicle and pimp it... hire some thugs... His buddy at the Electronics Factory catches wind and smuggles out a few prototypes.... Word spreads about this dude and his manifesto... more followers join money comes in... and it builds from there.
*shrug* Its plausible provided the system fails to notice what's going on until the terror-org has built up a large force. Kind of like how we let home-grown nutcases build up huge arms stashes THEN raid them.