It's rooted in societal culture and what people incentivize (ie assign the highest multiple to).
Until Americans take on a mindset of longterm/family (as I've seen many Chinese families express), they'll be doomed to make short term decisions. Right now very few Americans are able to accept an optimization that looks like "I invest today, and my grandkids will get the returns". So America is stuck in that local maxima of invest for next few quarters. The obvious tradeoff being the risks/ability to predict the future.