Are you looking for the real reason behind the massive declines we've seen recently?
The answer is 2 words = Interest Rate.
The US is going to keep on raising it and investors are looking for save haven that pays sure dividends ... so the US Dollar that everyone has buried in the last decade is outperforming all the Cryptos, and soon the EUR/USD will hit a parity (it's $1.25 now, it won't stay like this for a long time).
History always repeats itself, one way or another.
It's nothing to do with interest rates - they would need to be in the 1000s of percent or more so that inflation becomes 1000s of percent as well, thereby significantly decreasing the value of fiat/ USD. Interest rates of 1% have very little impact other than a tiny cost to borrowing and very long term impact on GDP. They have no effect on the price of bitcoin and other coins.