that means we have to hold long holdings if the assets we have go down for a long time. yes indeed it is the most normal and safe way because there is no risk of losing more assets unless the market experiences a deeper fall.
If you can prepare enough knowledge and skills, you will be able to choose good entry points, that in turn help you to reduce the waiting time and reduce probablity to see coins fall down for so long, and so deeply after you buy them. It's hard skill and take time to use it effectively.