That's a fairly dark view and I think a misunderstanding of what polyamory is. Couples looking to non-monogamy to solve their relationship issues is not what polyamory is, that's not healthy. Non-monogamy != Polyamory, ethical or otherwise. While polyamory takes many forms, all of them include mutual respect and communication between partners. Polyamory is having love for one or more individuals and actively being in a relationship with those individuals. I don't think you can ever expect one person to be everything, and I think for some polyamory is an alternative to leaving needs unfulfilled.