Market trends tend to be fairly reliable. For the most part, you see a bell curve of sales for successful consoles: sales are lowest near the start, then pick up gradually over the course of a few years until supply meets demand, and then the sales slowly taper off, roughly at the same pace that they went up by (though generally speaking, the tapering off is a bit faster than the build-up).
Consoles which don't take off generally hit their sales peak within their first two years, and then taper off drastically, usually with only brief recoveries during the holidays. Also noteworthy is that the number of units sold by this two-year mark is almost always 33% to 66% lower than whichever console is "winning", after curve adjustments to align the launches. It's not a constant, but it does happen most generations. There simply is no such thing as a three-way tie. The closest you get is the battle for second/third/fourth/whatever places.
Sky Render - Sanity is for the weak.
