~ 10/15 accident of USDT, which caused a sudden & incredible price increase of bitcoin/eth,
there was no bitcoin price increase! you were mistakenly looking at Tether/Btc and thought that is bitcoin price. instead you should have checked USD/bitcoin to see the price did not change.
Really? I'm looking at BTC/USD chart and there's a huge spike from 6200 to almost 6800 on Bitstamp. Bitfinex went even higher. And it didn't go back to 6200 from there, even weeks later. It looked like a sign of volatility on USD markets.
I doubt BTC is ever going to be stable. Maybe in 100 years if people abandon fiat completely.