One possible problem is that there are always more people willing to step in. I assume that I can still find a Japanese to English dictionary by searching Google. If one, or N, such websites get taken out by algorithmic flaws or bad actors reporting competitors, then others will simply rise up and take their place (or Google will subsume their content into the instant answers section). In this way, Google may not really be losing anything even if they are constantly burning their partners - there are always new partners coming up.