Getting back on topic here:
Here is the root problem of everything you have posted, be it your views, Heiko's views or whoever. The conclusions are drawn from the myth that what the Discus eats in the wild must in turn be the best possible diet for the fish. As John pointed out, this isn't the case at all. Sure they have adapted to survive under those conditions, but your naive to think that if a foreign food substance was introduced into the amazon, the discus would not take advantage of that as well. If this new food source was constant you would witness a higher population density of fish per acre.Proper feeding of fish is one of the most important factors in maintaining the health of it in our tanks. To choose the appropriate type of food species, it is necessary to know about what they feed on in the wild.
Likewise, man can and does replace what an animal might normally feed upon in the wild, and in most cases improve upon it. Do they stumble upon the way? Of course they do. Is there a better alternative to beaf heart/beafheart mix? Probably so, but that is not to say a natural diet is actually better for the fish.
Everyone always assumes that if something is natural, it is better. Many theorys are predicated on this myth. Some are true, many are not.