It could just say that he lacks imagination or doesn't feel that his attire is something on which one should spend a lot of mental capital. A suit is practical,

It could just say that he lacks imagination or doesn't feel that his attire is something on which one should spend a lot of mental capital. A suit is practical, easy, and non-threatening and picking up a bunch of cheap ones is a simple way to look professional without a lot of thought. It's really easy to look like a slob in a t-shirt and jeans and I suspect that a lot of SV CEOs put a deceptive amount of effort into their laid-back appearance. It's worth noting that Dell is a Texas company, and the t-shirt and jeans look is still a pretty specifically SV trend.