This recent  [article][1] claims there is research that quantum entanglement explains the arrow of time i.e. macroscopic irreversibility. However, as I understand, coarse grain irreversibility has been been demonstrated for theoretically and by numerical simulations for purely classical idealized systems like "billiards" and "gasses" in 2 and 3 dimensions. This would imply that, while there are deep connections between quantum entanglement and irreversibility, quantum entaglement is not strictly necessary for irreversibility as the above article seems to be claiming. What am I missing?

  [1]: http://www.simonsfoundation.org/quanta/20140416-times-arrow-traced-to-quantum-source/