I agree. Set theory is more powerful and flexible than taxonomic trees (although not perfect). It's why I believe the future is Table Oriented Programming (TOP), where code blocks are either in or managed by RDBMS. Code-centric tools rely too much on file trees and other trees. If you instead try to design your stack and/or language around sets, you'll probably end up with something similar to TOP.

https://news.ycombinator.com/item?id=33413124&p=2#33415249