Are you talking about taxing unrealized capital gains?
Because for the situation where capital is directly replacing labor, the income generation is taxed regardless of the whether it’s generated by a human or machine.
If I hire people to make and sell hot dogs, they pay taxes on their wages. If I build an automated hot dog vending machine, I still pay taxes on the profits of selling those same hot dogs.
One can’t spend any of the money until it becomes personal assets. So what is not being taxed?
If I keep them in the company, I pay corporate tax on profits (22%) for retained earnings. And then I’d have to pay dividend tax (either 15% or 20%) atop those retained earnings to pay them out to myself as income. Or I pay myself a salary and pay regular income tax on the full amount.
Due to our progressive tax brackets and double taxation of dividends, both options end up with larger tax rates than when dealing purely with low wage human labor. We as a society collect more in taxes from one high income earner than multiple low income ones.