Somchai? You sound like a racist.
Is a cheap helmet better than no helmet or not?
I am not arguing that riding with a helmet is not safer than riding without a helmet, nor am I arguing that an expensive helmet is (generally) not better than a cheap helmet, so I'm not clear what you're about.
I've had six motorcycles, a mini-bike and a go-kart. Sold the last one in '88, so I know little of modern equipment. I also had access to a company bike (typically Waves) for the over twenty years I worked in Thailand, but only rode it occasionally around the plant. I've had a number of accidents on bikes, one of which was serious. I quit riding because after my last accident it was not fun anymore.
I wish everyone would wear a helmet, but I never liked wearing a helmet and I have no interest in compelling others to wear one.