Currently the value of a stock is whatever someone is willing to pay for it. Who decides what the value should be, in your scenario? A government department?
If necessary, yes. Otherwise its just fraud. "Whatever someone is willing to pay" doesnr make a thing valuable; it just makes the buyer stupid. If I sell you a rusty old tricycle for $6000 just because you have a psychotic nostalgia for it, the value of old rusty tricycles doesnt become $6000.
Elon bought Xitter at what, $45/share? It was never worth that much...he tried to manipulate the stock value (i. e. commit fraud) and a government official forced him to commit.
That would work maybe...so you'd have a government body to assess companies like houses are currently assessed. Sounds expensive though. We'd need to raise taxes, which is probably a good thing anyway
It wouldn't involve raising taxes as much as it would involve collecting taxes in the first place from billionaire assholes hiding their wealth. This is a recent problem and is easily fixed.