Wealth* that is not doing anything has no effect on the economy. Suppose I had $100 trillion in cash (or art, or other useless commodity) in a vault somewhere, and never spend a dime of it. How is it impeding the economy? If I didn't tell you about it, you wouldn't even know it existed.
It's only when I start spending it, to redirect labor per my wishes, that I start affecting the economy. If I spend it all on yachts, that will cause a lot of labor and materials to go to yachts that won't contribute anything to the economy once built, instead of going to something more productive.
*Using "wealth" to mean fiat money, or art, or anything that has no productive use. E.g. if the wealth was instead in the form of idle farmland, that would be used to grow food if owned by someone else, then yes, that would be impeding the economy. So one must distinguish between wealth with inherent value, and wealth that only has value because people are willing to pay for it.
Actually that would result in a manufacturing industry. The problem is that if you wanted to buy a Yacht in say south Africa you wouldn't manufacture it in South Africa despite the mass unemployment problem.
but it does exist and is "missing" from the economy (i.e. other peoples pockets)
No, but people constantly shout "money printing" when the money supply goes up even though it could be as a result of people producing more physical capital.
Imagine producing more physical capital and being told you don't deserve liquidity in proportion to the capital/value you produced. That is the problem with a fixed supply currency system like the gold standard.
Why is it a problem to keep the money supply fixed? Imagine a theoretical economy where 100% of the money is in the hand of a single person. Even though the rest of the economy is able to produce and barter, it would be far more efficient to use liquidity i.e money to facilitate the division of labor. That one guy with all the money is effectively blocking the public infrastructure we call money. Transactions that ought to happen don't happen. Money doesn't fulfill its function as a medium of exchange. Therefore it is only appropriate to tax people in proportion to the damage they cause to the economy by excessive patience and holding excessive amounts of liquidity. It like an illegal parking fee intended to keep the streets free.
The amount of production is not impacted much by how how many bushels of wheat, or days of labor of the average worker, we value the Mona Lisa. Art can be wealth, but not all wealth is a factor of production. Labor, land, capital are all factors of production that influence how much stuff is made.
Making sure that everybody has enough to survive, enough to thrive, and enough to be creative and innovate or achieve what they want should be the goal. Distribution not only of wealth, but perhaps as importantly, distribution of responsibility and authority so that people can make the best possible decisions for themselves. Redistributing away from the accumulation of power/wealth into too few hands is very important for that.
Slumlord properties have the same theoretical problem as land, in that concentrated ownership can act as an incentive towards bad management; there's not much economy of scale when it comes to managing rental properties, so policy should incent dispersed ownership instead.
You can't be incentivised to create art when you will never realize that incentive. And unlike music record labels, it's not like you are giving someone else your earnings in exchange for editing and technical help and marketing.
Art was a bad example, though, since it's mostly just used as a tax dodge. The real problem is rent seeking.