Not saying a "virtuous circle" can't exist, they certainly do. However, it's good to keep in mind that a virtuous circle is by definition a feedback loop, and t

Not saying a "virtuous circle" can't exist, they certainly do. However, it's good to keep in mind that a virtuous circle is by definition a feedback loop, and there are other kinds of feedback loops which aren't nearly so desirable. In fact, taking a very dim view, one might say that "virtuous circle" in this context, and "tech bubble" are synonymous in denotation.