[metamemetics]

Wealth is the ability of an entity to create change.

Skills you know, your business network, your emotional support network, assets you can exchange.

People with great wealth can affect the world in profoundly positive or negative ways. In other words, wealth is closely tied to the notion of power.

A member of congress who has relatively low networth could have as much financial influence as Bill Gates. While this power is not as liquid or easy to exchange as cash, it is still exchangeable and a store of value.

[ To directly answer the OP: No we should not exclude speculation, everything is speculation to some small degree. Even holding everything in cash is a speculation on that nation's currency. We'd have to use other measures to estimate expected security\longevity, like liquidity of assets. ]