You're mixed up here and so are many other HN comments about finance. Banks and markets are the middle men. They move the money around. If money happens to flow into investment pools, the money doesn't go there to die. Those pools in turn invest into things such as car part manufacturers. We need these middle men to make the money flow easier and more efficient.

The place that wealth gets destroyed is at the investment level (in your definition is the economy). At my previous company, they spent billions on plants and they very often sit idle... like 95% idle. That is where the wealth dies.

Google moving the money around from one pool to another doesn't destroy value. Google laying optical fiber down then abandoning it does destroy value.

Most nations are shifting or have shifted to a service based economy, which means that most of the exchange of money is for a service, not parts, materials, etc. Services are often meant to augment the lives of individuals and businesses in different ways.

A lot of folks complain that companies like Google have made so much money that they don't have anywhere to spend so they start to hoard it instead of 'helping the economy'. The reality is that for a company, it is better to wait instead of investing for the sake of investing without considering the returns. It is also worth noting that when a company makes so much money, they often shift a portion of their business into the 'Financial services' segment of the economy.

I find it difficult to sell the idea that banks, etc are not part of the market. For example, without a bank loan at X% interest, some industries wouldn't exist. Without insurance for X product, a lot of companies and technologies wouldn't exist since insurance impacts risk level, etc.

I like to view this as an interconnected series of pipes through which money flows. It always flows somewhere else although some percentage spend most of its time in large tanks. Or in the case of Google et al. flows out of the tank, into adjoining ones, and then back in again. When a recession hits there is less liquid in the system, the flow slows down and cut off from some sections of pipe.