The kind of risk he's talking about is really investment based. You know, quite frankly the kind that Nintendo does is better for the industry than what Jack Tretton is talking about.
Sure if you wanna go on a straight line, and you really want to go far you have to be a little risky. Sony has been very good at that, in fact they've made their share of contributions on that end extensively, and continue to do so.
However, the entertainment medium isn't just going on a straight line. This is not a technology business. Sony used to grasp that at the beginning, but somewhere along the line they became so fascinated with advancing technology that they lost focus on the fact that, at its basis, gaming is really just entertainment, using technology(not the other way around). And entertainment isn't meant to be a straight line indefinitely, especially when the same old kinds of technology have advanced so much already.