Your Opinion Please: Creating a modern WordPress Theme using BS, BP, SASS, etc..

I have a few questions and thoughts I’d, very much, like this communities feedback on:

1. Why did WordPress Core release Twenty Fourteen without Bootstrap, Boilerplate and SASS?
2. Why is the documentation and process of creating Theme Options so… blah… compared to Redux Framework or Advanced Custom Fields (which I understand is under consideration for being incorporated into the core around WordPress 4.0).
3. Why is the Template Hierarchy still dependent upon page *files* (page.php, index.php, archive.php, etc…) when it could be organized in a single functions.php file structured like this:

class template_hierarchy {

// This replaces archive.php. If you are making a Child Theme of this then you would copy this function into your functions.php files and revise it accordingly.
public function archive() {
// The contents of the former archive.php file would be included here, essentially.
while loop yada yada...
}

}