Yes you are right friend, but in my opinion it is not only the DCA technique that will make long-term investors in bitcoin potentially profitable, but other buying methods I think will be equally profitable if hodl in the long run.
DCA method has absolutely nothing to do with your future profit, is just a strategy meant for bitcoin accumulation this strategy is mostly used by those new Investors and also those that can't afford to buy in lump. Moreover some people feel that doing the DCA is less stress than buying in lump since DCA gives them the opportunity to buy with any amount, The only different between this two method is that a guy who is buying in lump is always faster than the DCA Guy that's depending on your weekly purchase, but that doesn't mean that a guy who is buying in lump sum will be more profitable than the DCA Guy. Moreover your investment goal May be different from the guy that is buying in lump.