A slightly different version was in use in Denmark:

a ship declared the value of their cargo for toll purposes. They decided the price, but the catch was the customs could buy the cargo at that price.

That is fiendishly clever.

It sounds nice in principal but I think it’s not so easy in practice, if I asked you what’s your car worth you probably say something along the lines of well it would cost x to replace it, or I paid y for it, or I could sell it for z on eBay (all three different prices) but if you then said that well whatever price you say someone can buy your car for and you’re stuck with without a car while you go figure out replacing is actually a price is not any of those prices, and is probably higher than the actual value, and may even be higher than the cost to replace it - you might say that’s the idea but ultimately it feels creepy to make people pay a tax to avoid the risk of an asset they rely on not to be taken away at an inconvenient time…

The value to me would be the replacement plus hassle value.

There's clearly values I'd easily accept, you offer me a hundred grand for my car and you can take it whenever you want.

Now for regular items like a car this would be hard. How do I value it and how do I not get caught out when second hand sales spike and I don't follow the markets?

But we're not talking about everyone's car. We're talking about asking the state to forbid others to make or build certain things (yes I know it's more detailed but you get the meaning).

Yep but that’s kind of my point - let’s say your a poverty level worker with a POS car “worth” $2k but it’s reliable and you need it to go to work, and finding another one for a solar price carries the risk of finding a lemon or having unexpected bills your going to end up saying it’s worth $[4]k because it would be a really bad day for you not to have your car and taking the risk on a replacement is just not worth it. You end up paying a higher tax rate than the guy that’s got three cars in his garage and his happy wearing the risk over time of being slightly under replacement value since it lowers his effective tax rate and if he’s out a car for a bit at slight loss that’s no big deal..

That extra “value” (or tax on people) you ascribe to your car may or may not be distributed in manner that societally makes sense

alternative: anyone is able to make it public domain for that price

This creates a clear and obvious arbitrage opportunity that finance people on Wall Street will exploit almost instantly.

Ok? It results in them paying taxes while they hold it, to the value they ascribe to it. If they say it's higher than the original buyer, we get more in tax revenue

Or have I misunderstood your point?

You’ve misunderstood my point. This is formulaic finance math. In normal finance markets, there is a natural equilibrium where markets fully value the risk of mis-pricing the asset as part of the asset value. In the scenario outlined, only one party in the market is taking that risk, which means any financially savvy third-party can basically make free money off assets owned by others almost risk-free under a wide range of scenarios. Instant profit while producing no value. It would create an entire parasitic finance industry dedicated to exploiting it. You won’t generate much tax revenue if you destroy elementary mechanics of the economy along the way.

It may not be intuitive how the math works but this would be exploited so hard it would cause serious social and political issues. I don’t have a dog in this fight, I am just savvy enough to the math to see how bad an idea this is. Which is probably why no government has seriously attempted it even though it is an old idea.

Could you outline a single example or at least provide a reference to understand this more? I'm not at all getting what exactly these third parties would do. How is it different from just putting up items for sale with a price?