I doubt that there is a strong and decisive case in terms of “facilitating research progress” for having different tier journals (top, middle, specialty, etc). There doesn’t seem to be much hard, empirical evidence that peer-review provides a strong and credible signal of research quality/importance. However, as noted by a blog on The Economist, some of the other reasons for having top-journals may be important. They quote Cheap Talk:
“The full return to a 10-AEQ-page article in the top journal is thus estimated to be a 3.8 percent increase in salary.” (AEQ means the article is adjusted for page size to correspond to AER page length.)
And in an e-mail to Economist, Mark Thoma claims that the “separating the wheat from the chaff for overwhelmed readers” argument doesn’t actually hold:
Nobody reads the journals themselves much anymore, but where a paper hits is critical for promotion decisions. That's where the pecking order is established. The sciences are trying to break out of this, to some extent, but econ is a long ways from doing that.