Or maybe the writers just don’t want a girls show full of mechanics and grease monkeys?

I think the setting is that there IS motorization, but maybe resource is scarse or Ponies just don’t really need transportation because they’re equines so it didn’t catch on as well.

Interesting point about ponies not needing cars. The SSCS6000 makes a lot more sense when you think about it that way. Flim and Flam didn’t need it to get around, they needed it to carry the cider still.

I mean it seems likely that they just don’t use motorization to the degree we do. They’re fast enough and have enough endurance (as ponies) to be able to traverse longer distances more quickly, and with heavier loads. They also don’t appear to have an extensively developed infrastructure. Perhaps Equestria has 50’s to 70’s tech, but cars are only a recent development?

@BronyHeresy
 
Not widespread dosen’t mean only a pure numbers ratio of people posses something, it means only the rich or those in a position to manufacture the item posses it. Before Henry Ford used the assembly line to make cars affordable to everyone, only the rich could afford motor cars. (does this make Flim and Flam Henry Ford?). Ponyville is a noticeably poor town, with only Filthy Rich and Rarity demonstrating any degree of wealth, and they do not posses motor vehicles. The point is that if cars exist on a large scale and aren’t something only Flim and Flam have come up, nopony in Ponyville would be rich enough to have one, let alone enough for a parade.

@Trickquestion  
Widespread would be like everypony has a car. I haven’t yet watched the ep, but if you’ve got a dirt town like ponyville, it’d probably be no more than about 12-24 floats. That’s like 12-24 cars. Again, even if ponyville is a dirt town, that’s easily 700-1500 people, and probably lots more than who we’ve seen on camera. Towns are bigger places than the people you really see. So about 1 car per 50 people. Not a whole ton.
 
Besides, Applejack’s truck. We already knew they had motorization.

@BronyHeresy
 
If they aren’t widespread, how was a dirt town like Ponyville able to crank so many out for something as frivolous as a parade?
 
Either the parade started at the top of a hill, or each float has a pony on a bicycle powering it.

I’m fine with motorization, but it seems clear that it’s not too widespread. Equestria may simply develop differently from earth. Tech isn’t a strictly linear progression. Exempli Gratia, you could have a world that never developed gunpowder, but has internal combustion engines.

Clocks don’t emit puffs of smoke.  
There’s some type of combustion going on.

They don’t even go that fast. Also, no visible motor, so possibly clockwork cart?

Clock work maybe?

Good point.
 
However, this was somewhat already established in The Super Speedy Cider Squeezy 6000.

The Super cider squeezy 6000 was also a selfpropelled vehicle.