http://en.wikipedia.org/wiki/List_of_PlayStation_1_games
A list of PS1 titles, how many casual and crap titles you think there are?
http://en.wikipedia.org/wiki/List_of_PlayStation_2_games
ditto?
http://en.wikipedia.org/wiki/List_of_Wii_games
It happens with the market leader in hardware, the evidence is right there.
Now for comparison -
http://en.wikipedia.org/wiki/List_of_Nintendo_64_games
About as many released over its lifetime as PS3 have up till now.
http://en.wikipedia.org/wiki/List_of_PlayStation_3_games
Conclusion - There is no way of preventing bad or under developed content on the highest selling systems. There is hope that with time and patience better games will be produced though.
“When we make some new announcement and if there is no positive initial reaction from the market, I try to think of it as a good sign because that can be interpreted as people reacting to something groundbreaking. ...if the employees were always minding themselves to do whatever the market is requiring at any moment, and if they were always focusing on something we can sell right now for the short term, it would be very limiting. We are trying to think outside the box.” - Satoru Iwata - This is why corporate multinationals will never truly understand, or risk doing, what Nintendo does.
