Why do writers still employ archetypes today?

Because no matter how much our environment has changed throughout the years, the core Biological instinct that makes us human is still pretty much the same.
for example, back then in order to eliminate our competition, most of us picked up our weapon and kill them. Now, we formulate strategies to make them goes bankrupt and out of business.
The method is different but the principle is still the same.

Reflective writing