As every coder knows, the best way to learn to write good codes is to read some established open source projects, such as those from Google. Such kind of resources are very easy to get on the web.
A part design with elaborate history is in fact a coding project. But it seems to be very difficult to find many high-quality "open source" NX parts, especially sophisticated ones. This makes the learning process very slow. And I don't think this is in the interest of the software producers.
Therefor I'm a little confused by the marketing strategy in the CAD software industry.