Why is it hard calculating what someone's income tax is? Well, when you dig into it, income isn't an integer. It's an arbitrary object which can support a stupidly high number of interfaces.
This is true of many, many objects which are relevant in tax.
Oh boy.
Except that's also a lie. C corps are actually a family of ~50 trees of abstract classes, most (but not all) of which have one implementation. Ditto LLCs.
An LLC can be shareholder in a corporation which is a shareholder in a corporation which is a member of an LLC which is a member of the first LLC in this sentence.
For example: all Atlas companies, at present, are Delaware C corps. That reduces dimensionality by a factor of over 100.
Over time, the hope is that "an Atlas company" implements the interface "Delaware C corp" (or similar) where you need that to plug into legacy infrastructure, but is transformatively better.