I think you're missing the point of DCA.
DCA recognizes that we can't know what the price will be at any given time. If you lump sum buy on any given day, you don't know if the price will be higher or lower in a week. So maybe buy today and miss out on a better price a week later. With DCA you don't have to worry about trying to guess the best time to buy.
That could work assuming that from the moment you decide to buy there's exactly equal chance of bitcoin going down as of it going up, but this is not the case.
Bitcoin is a growing asset that follows the adoption curve and as long as it exists and meets the demands, it will continue to go up.
Let's not forget that bitcoin tends to follow cycles, so it's not that hard to buy bitcoin in a relative low (50% from the ATH). If you did this easy and simple thing over the years, you'd always display better results than most traders, including the ones who DCA.
Don't believe me, check how many 50% corrections there were since 2013 and do the math for any given period comparing DCA method with a 50% lump sum buy with the same capital.
You'll see that the simplest method produced far better results every time.
And with Bitcoin, since we have something that basically supercharges Bitcoin investing - the 4 year market cycle - by telling us what periods of every four years we should be buying, we can then use that to our advantage and greatly increase the returns of DCA. So we can DCA only during the lower part of each 4 year cycle, like buying starting once Bitcoin has crashed a lot, and then continuing to buy until it goes above the old ATH, and then wait for the next crash, saving money in the meantime to be able to DCA with extra funds on the next bear market.
That's not the best idea if you ask me. Let's take this year. If we followed your advice we'd be buying until the new ATH, so we'd be buying 66k -73k and now during the correction we'd be holding that at a loss, right? Now let's say it doesn't go to a real ATH and just crashes 50%, you're going to be stuck with the coins you bought using DCA since February and trying to get funds to buy more, since now it's the dip, a moment you actually should be buying, but your money is stuck in $70k bitcoin.
And with DCA, instead of guessing when to buy during a bear market , and many people would likely lump sum well before the bottom, or assume a lower price is going to come which never does and then they have to lump sum well after the bottom, DCA allows buying consistently all through the bottom.
Why not simply buy it during a correction and hold. Does it really matter that it wasn't the exact bottom? Last bear market I was heavily buying everything between 25k and 19k on the way down, as it was a good price to pay. It went lower and I did not buy because I was out of money at that point, but I still think I did better than people who caught that bottom using DCA, but were spending $100 a week instead of going all at $20k.
DCA removes the risk of being wrong about when to lump sum buy, and of course it also means people don't have to save up a bunch of money first before buying. Lump sum buying is ONLY better if you happen to have a bunch of money at an ideal time (bear market) and you guess well enough where the bottom is to get near it.
Are you really "wrong" when you don't buy at the exact bottom? Who cares? When you DCA you also don't buy the bottom, you just make it look like you do, because buying the bottom with 1% of your capital doesn't really cut it when 99% of it does not buy the bottom. It's like running from the cops in your car 10 times and 9 out of 10 they catch you and put you in jail, but one time you run away and you feel good about it and brag to people that there was one time you managed to outsmart them