I understand your point, but how long will you wait for bitcoin to dump considering the fact that it's quite difficult to perfectly time the the market? I would rather not see bitcoin dump right now. Instead of waiting for bitcoin to dump, I think DCA will be a perfect opportunity for you. It would demand consistency from you and ofcourse you know, consistency pays off. Adopting the DCA method of investing will help you manage risks effectively whether the price dumps or pumps. You can still buy lump sum when the price finally dumps if you so desire it.
And why on earth will you even keep waiting till the price of bitcoin drops when you can buy when ever you feel like because that is like the best thing to do, when the price might be down you might not have the funds to be able to buy so it is better to adopt the strategy of buying when ever you have money to buy that is like the only way you can help your self that's the way foward.
DCA is one of the best strategies that can be used to manage how you buy so it will not a bad idea and a lot of people are always finding it very difficult to know exactly how to buy they are always complaining that they don't know when to buy and you made a very good point so it won't be a bad idea and when you start buying it won't be a bad idea when it comes buying anytime is okay.
And when the price is down everyone will want to buy but there people that will not buy even if the price is down all they will do is to complain about one thing or the other.