Yeah, sure the more problematic portfolios would have been the ones who made decently large BTC purchases towards the top of the BTC price range, and then his subsequent DCAs at lower prices were not enough to overcome the earlier lump sum buys at higher prices, so there surely can be some BTC portfolios that might take a while to get back into profits, even after several years of ongoing BTC buying.
On a subjective viewpoint to me it doesn't seem that problematic as others may be projecting. Due to market uncertainty we should be flexible with our timing plans while accumulating our portfolios be it for a long term or short term accumulation plans.
Having bought a lump sum at a higher price, what the investor needs to do is to adjust his plan giving it more time and if possible he/she can accumulate more BTC while patiently waiting within the adjustment period. You don't lose in BTC DCAing if only you can be patient with the market because it will surely take you back to profit. The only time anyone loses is when they panic sell out of FUD or impatient.
There could be a variety of scenarios in which a newbie started out his investment into bitcoin at the top, including front loading (or lump summing) the investment at or near the top, and so it could be the case that he knew that the BTC price might go down and he just wanted to be prepared for UP, so he lump sum invested just in case the BTC price went up, and yeah, as you mentioned, he may well have accounted for that and already had a plan in place to continue to buy with extra funds that he had held aside for such purposes or alternatively to continue to buy with whatever portion of his disposable income that he would have available on a weekly basis if the BTC price went below his purchase price. Of course, he could DCA in or he could have even set up predetermined buy amounts at various dip points, so he could combine DCAing and buying on the dip to attempt to lessen the blow of his having had bought higher, which also would end up bringing down his average cost per BTC from the price of his initial lump sum purchase.
Another possibility is that the guy might have had made a mistake and used all of his available money and potentially even gotten out a loan, so that he was pretty much all in bitcoin at his first lump sum price, and then he might not have any extra money to keep buying BTC, and he is using any extra money that he has to service the loan that he had taken out. Surely, we can see that this second situation is worse than the first, and surely the guy still has good chances of still coming out o.k... .but he might have to wait several years to get back into profits in the event that his discretionary income or situation does not improve in such a way that he would be able to authorize more BTC purchases in order to bring down his average costs per BTC. Surely the guy might also had come into bitcoin with a certain budget that he was going to use for buying bitcoin and that he was not going to go higher than his allocated budget.
Even though there are no guarantees in bitcoin that the BTC price will continue to go up, we can likely see that a guy who has various plans to continue to buy might be better in circumstances that the BTC price dips after his initial purchases, yet surely people are going to have their own ideas in regards to the BTC investment strategies, and some people will have been better at planning and/or having some flexibility to roll with the punches than others.