The idea of a wealth tax is neither new, nor etched in stone. The Altman proposal is but one of many dozens of ways of taxing "wealth".
Wiki offers a fair overview here:
Wealth tax - Wikipedia, the free encyclopedia
But this does not cover the possible scope of what could be a partial solution of the debt problem.
ie., this 1999 proposal by Donald Trump.
Revenue: In 1999, Donald Trump proposed for the United States a once off 14.25% wealth tax on the net worth of individuals and trusts worth $10 million or more. Trump claimed that this would generate $5.7 trillion in new taxes, which could be used to eliminate the national debt.[6] A net wealth tax may also be designed to be revenue neutral as where it is used to broaden the tax base, stabilize the economy and reduce individual income and other taxes.
(remember that in 1999, the US deficit was much smaller than it is today)
Another means of taxing nonproductive wealth is that used by India.
Filing wealth tax return: Things to know - Economic TimesSimilar to what we used to call Luxury Tax.
The wealth Tax would not necessarily be a one time, or an annual tax. The tax rates would likely be progressive. I have seen some proposals that would not even touch the first 2 Million Dollars of wealth.
The taxable amount might not be based on total wealth, but some part of the wealth, as in the India tax, or it might involve some part of corporate assets, such as the dollars that corporations might wish to "repatriate" from foreign operations.
I think the first thing to be decided is whether or not the only source of tax revenue should come from earned income.
On another thread, I suggested that one possibility for a (wealth type)tax might be a limitation on inheritances which might be something like a maximum of 20 million dollars per person in the current and next two generations of a family. A dynasty tax.
If the final answer only involves a reduction in SS or Medicare/Medicaid and an increase in the highest tax bracket to 39%, I fear that we'll come up short.
If this isn't possible in the current congress, perhaps a start in investigating alternate ways of reducing debt should begin now. We can be assured that if this does not rise to discussion level, that there are interests who are at work to maintain status quo, or worse.
Just my opinion.