If other companies are making lots profit doing something then it isn't a terrible idea. A terrible idea is trying to build something that will never make lots of money, like the pet dating sites or so.

Like the songs that Joe Cocker often covered, the ideas may be languishing, with little-to-moderate success.

Until done properly, or combined with other ideas or good marketing.

Until they make money, they are derided as "terrible ideas."

Of course some ideas are hard to recognize as good, but you can't say that there aren't any terrible ideas out there. Trying to implement a terrible idea will never work out no matter how well you execute, unless you make it into a MLM scam but I wouldn't call that success.