I don't question that their income from what ever source should be (highly) taxed. However the wealth tax should be on top to fix the errors made in the past (and are currently made) leading to such accumulation of assets. The question is how should non-liquid wealth, such as estates, shares and bonds, be taxed.

Yeah and then they pay interest on that loan, which is income to the lender for them to pay tax on; then when the original loan comes due the billionaire either refinances and pays even more interest, or pays back the loan by selling their appreciated assets and then - yes - pays tax on the income. So either way the tax is getting paid, now or later, and you have no idea how frustrating it is to see people parroting this over and over and over, and downvoting you for pointing it out.