Ok, then you use your math to buy stocks and I'll use my definition, which is the one accepted by everyone else. I'll gladly be here with the idiots making bank, buying my overpriced index funds while you wait for them to return to their platonic price.
Reductio ad absurdum: would you spend one million US dollars to make one dollar a year? No, that's clearly foolish.
Would you spend one US dollar to make a million a year? Of course, but what such investments would ever exist?
And so instruments which bare gains over time have some value, which is calculated by the means of cost of investment to returns over time.
If there are a market of such instruments, they can and will be in competition with each other.
This "things are only what people value them at" stuff is for the birds. Those other people you're talking about are actually calculating their investments. Others with such mentality will follow, not knowing what they're doing, and taking missteps when the goods are already gone.
What you think is "accepted by everyone else" is what you're seeing at face value. There are reasons behind actions. Those actions in and of themself have no meaning without context.
The mathematics of investment have never, ever changed in any meaningful way. The history of debts, interest rates, and returns have always fluctuated, but the math hasn't.
The problem is that the future is uncertain, and price is guided by feelings and impressions. People think Tesla is a great company for a variety of reasons that have nothing to do with math. They trust Elon Musk, they think Tesla has a technological advantage, etc. Of course a lot of people also look at balance sheets and hard facts before making a purchase. The price of Tesla's stock is composed of the coordinated actions of all these people. It turns out that adhering to your narrow idea of value does not help you accurately predict the price of a stock, or even the market as a whole for that matter.
