Once we've proven that Bitcoin keeps rising every year, holding onto it seems risk free... this confidence is expected to persist as the asset continues to grow.
If you look Bitcoin with its yearly candles, you will see better growth of Bitcoin.
Buy at top, sell at bottom are for losers and if you look at Bitcoin max price year by year, it can make you disappointed as more people will be losers.
If you look at it with Bitcoin min price year by year, it shows you more solid growth of Bitcoin with time.
https://charts.bitbo.io/yearly-candles/