How do you explain then the sideways movement of BTC since months? Nothing happening in BTC-price. If everybody thinks BTC will go up, the price should then follow (because less people would sell vs. buy). So apparently people are selling. Predominantly the miners? No clue. We will know only after the last Bitcoin is mined what the true equilibrium will be.

You might check out (probbly have already) the rising star AMPL (https://www.ampleforth.org/), a coin that wants exactly this - to uncouple from Bitcoin, but not as a stable coin but as a coin linked to actual purchasing power!