DCA is for the retailers and only effective in the long term, should be at least a complete cycle or more to get effective results.
It must be those big guys are the ones who are mainly investing for the long-term, and the small one or the retailers are usually lacking in patience, so they can also sell early. In fact, a lot of big guys are already doing a DCA. Have you heard about Michael Saylor or his company Micro Strategy that keeps on accumulating BTC, even if the value of it is still okay or not really dipped?
I am not fan of DCAing either, on some days, you will feel great but on some days it feels like you are wasting the potential capital by just letting it idle and even continue doing it, knowing the bearish season is here to stay.
This is what I am talking about earlier, about patience. But this is also because we are too small to not have enough money, to not think about our investment for a while. But if you think it is a waste idling it in BTC, then what do you think is much better to do instead? To just idle the money as is, in a fiat form? We don't know that it had a draw back too. The value of it can decay though overtime. So we didn't really save a lot the moment we now use them for buying, when the dip finally arrived.
But one who got no knowledge or any trading skills and has the dream of accumulating a decent amount of bitcoin after 5 years of investment then this is one of the best methods.
Identifying a dip is even simple. But if we set a time frame, then we usually do our best too to maximize the results. Though no doubt, 5 years was still a long time. So if we also don't expect too much, and then as long as we are DCA'ing on the recommended level per month, then we still can accumulate a nice amount of BTC.