it just requires people with complete belief in Bitcoin's future potential. those who panic sell when prices fall, only think about taking the opportunity to avoid losses or secure their profits quickly. and hope they will wait at the bottom again to collect more.
if you want to buy Bitcoin, then do it right away. Don't delay if you plan to invest long-term. There is no problem if you buy gradually every time you have money that you allocate to Bitcoin. let's say $100 every week, that's not a bad thing. there may be investors who wait for the moment of decline and buy in large quantities to take advantage of lower prices. but if you don't have more money, you can accumulate your Bitcoins slowly.