This is the founding principle of the tax on assets in countries that have this tax:
If you have gainful employment, you pay tax on this income.
When you spend part or all of your income, you pay Value Added Tax (VAT)
If you do not spend all your income and put some money in a savings account, you pay income tax on earned interest.
If you invest some of your income in divided-paying stocks, you pay income tax on the dividends.
If you have a house built with some of your savings, you VAT on the materials and the services rendered by the construction company as per point 2 above.
Lastly, if you have been foolish enough not to squander all your income hand over fist as you earned it, you get punished with a tax on assets. That's what it is; the tax on assets is a punitive tax.
As the US statesman Benjamin Franklin said: "nothing can be said to be certain, except death and taxes"