You needn't make it obvious, it still works. At least a small percentage of consumers isn't stupid and will notice the difference.

Example:
My company offers two kinds of internet access products under two brand names. The cheap one is targeted at price-sensitive customers, the other one (much more expensive) is for those who expect quality. We don't, of course, even try to make obvious the weaknesses of the cheap product in the marketing material we have for the more expensive one.... The result would be a disaster, our competitors would be the first to point out that we ourselves don't believe in the quality of our products.

So we simply sell two products that have almost the same "data sheet quality" (speed, mailboxes, spamfilter, webspace) for very different prices. - Consumers do know. Those who need or want the better quality buy it. (Maybe they buy it because it's more expensive without knowing the details, who knows?)