I've been hearing "tax-the-rich" for years. I don't see this as a new discussion by any means.
While it is desirable for some kind of wealth tax, I have not heard of any solution that will work. Until then, I will deem a wealth tax as "cheap talk." Maybe it is talk to divert attention away from good ways to really tax the rich.
Increasing VAT taxes (and refunding low-income earners) is a good way to get more money from the rich. Easier to enforce than a wealth tax.
Applying a Tobin Tax to all financial transactions (something like 0.01% of the value of the transaction). Easier to enforce than a wealth tax.
As for the billionaires you mentioned, I would question how ethical they are with their own taxes. Would they open up their books to let us see?
Yes, there are some rich people who do understand their obligation to civil society. They willingly pay taxes. But too many rich people believe that they have John-Wayned their way into wealth. In their minds, they owe nothing to anybody--and we should be thanking them for all the jobs they created.
Here is an article I wrote in 2016 about a John Wayne: