No, a cheap card was binned at lower ability. 5000 cards and each gets tested. Some are sold as OC goodness for mora money. I'll never see a top watercooler buying a cheap card and overclocking. Overclocking is'nt a budget thing. You buy the best you can and deal with it.
Some companies build less capable VRM and mem abilities. Thus lesser costs to them, they pass that on to you. And less abilities for you. Cheap card, you overclock it and be sad. Or the smoke comes out. And thier warrenty is bad..............
You need to understand WC is based on physics. You can only do so much with ambient cooling and WC is the best for that. And econimics of chipsets. Non-reference boards, etc etc.
But it isn't Harry Potter magic dude. It's a lot more complicated. You'll learn as you get involved. Read here and at at other forums, in six months at 4-8 forums at 5+ posts you read from beginning to end in lots of topics, every day, you'll see what I'm talking about.