The SEC exists. As do many other mechanisms by which the government regulates direct and brokered securities trades and sales. You can make the case that some of those controls are poorly/ineffectively implemented, but you can’t claim that it’s not something the government routinely regulates, intervenes in, and sometimes prohibits outright.
https://www.sec.gov/files/forms-3-4-5.pdf
Here are Musk’s. https://www.secform4.com/insider-trading/1494730.htm
It's harder for private companies sure, but who will stand in the way of govts if they said we will sanction your if you buy X or Y company?
This entire argument doesn't really hold IMHO
Because the building is standing right where it is, in the open, lit by the sun every day. If you don't pay your tax, the government can just take it.
This compensates for the several philosophical and moral problems with it, and I've seen several economists declare it the best form of taxation there is.
I think a lot of tax authorities also don't really aggressively reassess that regularly without a sale, so it also kind of ends up baked in that if you didn't pay that much for the property, it's only theoretically worth that much.
I don't like property taxes either, and at minimum would rather they were called something else, and preferably replaced with per-service charges where possible.
But either way they exist to pay for things, and not to just degrade the value of your property simply because you worked to own it.
If a majority stock holder in a company sells all of their stock, the price first the first share sold is likely going to be completely different (and substantially less!) than the last share sold.
Personally my favorite idea for this stuff that I have heard thrown around is to allow people to self value everything. However, that self valuation then becomes a price tag. Let a billionaire's accountants put their own evaluation on their equity in a business. But that becomes a binding offer and some other billionaire could come along and buy them out at that valuation. That creates pricing pressure in both directions, the person is prevented from underpricing their assets due to the threat of another buyer coming in and a person is prevented from overpricing because it increases their taxes. And suddenly all the problems regarding how the government appraises these things disappears.
And that ignores that it trivially enables large-scale exploitation and looting by construction.