The processes you're citing are not the only way to form those polymorphs, but rather either the straightforward method for deliberately creating that form (e.g. shock tempering for form I), or a secondary one: notably, while form III does convert to form IV, the easiest way to reach form IV is simply by cooling at room temperature.
So that's the main answer: form IV is the predominant form when cooling at room temperature.
That said, the process is a bit more complex. Chocolate crystals aren't actually forming purely based on the temperature of the surrounding air, but rather on how fast it cools. Obviously a freezer cools the chocolate faster, but even at room temperature, the layers closer to the surface cool faster. So with uncontrolled, unmixed cooling, it's very likely that there will be small amounts of forms I-III formed, and they can potentially seed some small amount of additional growth of those types, even as the slower-cooling regions further from the air end up as form IV. Similarly, if there's enough bulk to allow the center to cool extremely slowly, some form V can form! The only thing you can't actually get initially is form VI, since it takes (order of) months at room temperature.
You can find this type of information incidentally in many articles alongside information about tempering; for example, here's a fairly science-focused article.
(I haven't found any quantitative analysis to give even ballpark numbers for the ratios of these forms, unfortunately - would love if someone else manages to contribute that!)
