Earlier quoted context omitted.
A wealth tax would also be beneficial in reducing wasteful stock buybacks. Without any benefits from high stock prices, boards and shareholders will be less inclined to impose those price targets on CEOs, CEOs will be less incentivised to "cheat" on quarter-based performance and the myopic share price performance view of their companies, hence will reduce stock buybacks and returning money to shareholders. That leave…
Why do you think a wealth tax would reduce stock buybacks? I don't see the relation.
Stock buybacks artificially inflate equity value - cash rich companies buyback their stock just to deploy that cash and prop up their equity value. CEOs love this easy trick because it increases their equity holdings' value, and also lets them hit quarterly share price targets which allows them to accrue more equity options. But at the end of the day, this money isn't benefiting the company, so it's just air.
With a wealth tax, the incentive to acquire increasing wealth dampens somewhat. You're only taxed once you cross a certain threshold usually, but once you cross it, the resulting tax hit can be quite sudden and severe. You hold equity but you have to hand over a significant amount of cash immediately, so you'd have to liquidate your holding, which is why a lot of HNWIs hate it.
In fact, it's why there are active strategies (usually involving philanthropy and blind trusts) in Switzerland (which has a global wealth tax) that allow to optimize your wealth just so you stay below the threshold. But at least, that wealth isn't being hoarded and is being actively deployed in other ways.