Gigabyte and zotac has the worst cooling materials on them ( cheap thermal pads) while maxsun and yeston have worst cooling mechanism over all but Msi, Asus, sapphire and others are the first on my list, they never failed me, I'm shocked you said they die easily it depends on how the owner took care if the cards, no matter which brand if care is not taken the cards will die fast
They probably do that to void your warranty with them because they know you will change the crap thermal things and doing so, they will not do do with you, yeah shady business, my take on this is to look for manufactures who puts the best thermal pads, so you dont need to change anything.