Some thoughts:
With Post Modernism, the design playing field has become flat. There are no more hierarchies, no single centres which can claim authority over aesthetics. All becomes equal. This can be confusing, scary, pointless, nihilistic. We can borrow, use, refer to, assimilate, include, appropriate, colonise, take (of course with-in academia the sources have to referenced ..to avoid plagiarism...out side ..to avoid law-suits!!!) any genre, technique, approach, culture etc. It's all systems go with no one system,or any system in place!
The responsibility is up to the individual to make meaning, develop value and become self-governing; developing one's own sense of morality. A spin-off could be a sense of being a one humanity. If I/we have become heirs?heiresses to all cultural heritages, it suggests that I/we then all belong to these heritages. The global-one-family-humanity?