In my opinion, the main reason why people deliberate more on the DCA discussion is because it is mostly practiced by new investors. Many old investors opt for lump sums. A lot of people cannot buy BTC and hold without accumulating some portion of it if the price dips because they feel unsatisfied with the amount of their holdings, or they are entirely into buying Bitcoin. You can call it an obsession or aggressive buying. Now, the safest method they feel for gradually accumulating these small portions of BTC is through DCA.
I don't know how you come by this conclusion but I think the opposite is the case; new investors rarely know anything about tge DCA method except maybe those who have the opportunity to know this forum. When you talk about FOMO that the DCA method addresses, it is common with new investors. They just want to buy as soon as they can as as much as they want. It is after a while of being into Bitcoin that they get to know certain approaches and models they would have applied that would have stood as better alternatives. On the other hand, those who have been in the business of buying Bitcoin for long already know the importance of buying Bitcoin using the DCA method so they apply it dutifully irrwspective of the price and are never in a hurry to sell.
What I feel you were trying to say is that the DCA method is more suitable for those with lower income as those who have large funds would prefer buying large quantities at their preferred price points. This is true to a large extent and seems to agree with recent purchases of popular whales.