The main reason for the cycles in crypto from my perspective is available global liquidity, not the sell pressure of miners. Countries like the US have to refinance their debt, and that used to go in 4-year terms for the largest portion of their debt. Now that has been changed to 5-year terms in 2021. So the majority (not all of course) of the US debt will have to be refinanced in 2026. That means the US government will require a lot of (cheap) money to be available to borrow and refinance their $10tn in bonds maturing next year