"Capcom sold 1M units at full price, that should be suficient to make them happy... retailers on the other side..."
I would say retailers are probably still happy as well - the 1M units will eventually be all sold, and the "bargains", while indeed lower priced, were not bottom of the barrel bargains, so even after eventually selling some of the games they ordered at a lower price, the retailers probably earned something on those as well (not to mention all the full priced games they sold in the first weeks).
"But my primary point was about not selling the first shipment in the first month(s) like what happens with some games, even if it is rare."
So in your book a game that shipped 100,000 copies and sold all of them in the first month is a success and a game that shipped a million copies but hasn't sold all of them but only 900,000 so far is less so? 
Currently Playing: Shin Megami Tensei: Devil Survivor Overclocked, Professor Layton and the Curious Village
Anticipating: Xenoblade, The Last Story, Mario Kart 7, Rayman Origins, Zelda SS, Crush3D, Tales of the Abyss 3DS, MGS:Snake Eater 3DS, RE:Revelations, Time Travellers, Professor Layton vs. Ace Attorney, Luigi's Mansion 2, MH TriG, DQ Monsters, Heroes of Ruin