This is actually the solution, not the problem. You seem to be assuming that the "correct" amount of tax to pay is the amount which is based on the market value of your asset. But the correct amount of tax is actually the amount which is based on the asset's value, to you. This keeps Blackrock from swooping in and buying up everything you own, since it's only worth market value to them.

It also doesn't make the tax onerous; a revenue-neutral switch from our current taxation scheme to harberger taxes would be revenue-neutral, whether it was based on market value or personal value.

Blackrock would definitely never swoop up a whole class of assets and then something to inflate the prices. /s

I disagree that the tax isn't onerous, but mostly from an administrative overhead perspective.

Like many people I'm taxed at source with minimal options to change my tax bill. I pay the going rate, as per the rules. Putting the obligation on me to do a bunch of work and worry about correctness would be a huge source of frustration and unhappiness.

If you're in the US, and you do the slightest bit of investing, your income tax is enormously complicated in comparison to a harberger tax, and fraught with potential penalties for gettting any of the numbers wrong. For a harberger tax, you only have to come up with 1 number, and you're the only one who decides whether that number was right or wrong.

If you mess up an income tax, it's easy to get your house taken away and auctioned, with $0 of the proceeds going to you. If you mess up a harberger tax, you get all the proceeds from the sale at a price which you literally just said you'd be happy to sell for.

The frustration and uncertainty isn't nothing; but I think if you were on the harberger system your whole life, and someone asked you if you wanted to switch away from it to the current US tax system, you'd laugh in their face.