Aside of Sony's Eye toy thingy they released for the PS 2, I'd say their actions prove that they are to blame....
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Anyhow, the game market is crap, long live Nintendo, but shame on them for only putting safety nets at their factories. Ruthless!!!
Understand your point of view but still I fail to see, apart from proprietary games, how Sony and Microsoft are directly responsible for what you, in my view, are clearly pointing out above is a result of what games houses know will sell and is the core reality of the mass market as confined by modern marketing.