Good Q,having lived here for a few years now you notice these things ,twice now ,seen a rear half shaft on the road looks if wheel bearing has collapsed ,or crown wheel /pinion ,due to lack of oil has collapsed whoe lot falls out.
Thai friend of mine has a car repair business he had in a Mitsubishi G Wagon owner had run it out of water cooked the engine had to replace the engine ,he said he is always replacing battery's ,owners never check water levels battery dry, plates twisted,replace only .
Our neighbour has a Ford pickup known them for a few years now ,far as i know never been in to Ford for a full service ,no money ,and I would say the no money bit is a problem with a lot of car/pickup owners
Thanks for confirming that you could not justify your assertion.
The "example" of your neighbour doesn't count as it is nothing but speculation on your part.
Replacing batteries that needed topping-up is not evidence of Thais not servicing vehicles in general, everyone has to replace batteries.
One empty radiator is not indicative of "Thais not servicing their cars".
And a couple of half shafts on the road. You're expecting it to be credible that you stop and forensically examine vehicle parts at the side of the road? Laughable.
Your "examples" when compared with the approximately 10.5m vehicles on the roads here mean nothing. Have you ever been to any manufacturers service department and seen how busy they invariably are with people having their cars serviced? Ever seen how busy Cockpit and B-Quik centres are? Why do you think that your friend still has a repair business - it's because Thais need places to get their cars serviced and repaired!