Voice acting does not sell games. Pretty screenshots sell games. Companies optimize accordingly.
(See also: Why do companies with engineering budgets in the hundreds of millions of dollars come out with websites that look like they were designed by an artistically talented 15 year old in flash in 1998?)
(See also: Why do companies with engineering budgets in the hundreds of millions of dollars come out with websites that look like they were designed by an artistically talented 15 year old in flash in 1998?)