I don't think the last five years have been normal enough to judge Bitcoin's long-term trend; it's been roughly the craziest six years in decades. Let's hope the worst is yet to come, something above $35,000.

Bitcoin isn't even two decades old, so talking about “decades” in the plural makes my head spin. Given that Bitcoin has been around for 17 years, talking about a 5-year period means looking at 30% of that time, which is a significant time frame.
Furthermore, it’s more common to rely on recent years to predict what might happen in the future rather than on more distant ones. We shouldn’t expect that with a price of $70K and a market cap of $1.41 trillion, returns will exceed 1,000 percent as they did in some of the early years. It is normal for an asset that matures and grows in price and market cap for returns to flatten out, as has happened over the past 5 years. While this does not mean the price will remain flat in the future, I do believe we should not have very high expectations for future returns (though if, for whatever reason, the future price of Bitcoin surprises us positively, so much the better).