There is no guarantee that you are going to be in profits with your investment even if you invest for 4 to 10 years or more and secondly you also need to understand that past performance is not a guarantee for the future performance but a guide and that doesn't mean we shouldn't put good efforts and good investment practices by buying and holding without selling too soon.
Have you seen anyone that invested in bitcoin 10 years ago and is currently at loss? Am confident that if you can hold bitcoin for 10 years, you will be in good profit. Do you think bitcoin will be at the current price which it is in the next 4-10 years? I don’t really think so, if you can take your time and check bitcoin price history, then you will know that bitcoin is really growing, and am sure in the next 10 years bitcoin price is really going to be massive.
Lots of people still don’t know about bitcoin yet, bitcoin awareness is still growing gradually, and even government are beginning to have change of mind about bitcoin, they are beginning to adopt bitcoin. With the way things are going currently, I will definitely use previous performance to predict how the future performance will be.