Well is not everyone that can afford one BTC once and it's not necessary or fixed that one should start with one BTC and above , but with DCAing one can actually do that, those that are making some extra bucks in this forum through campaigns can also have enough bitcoin in their portfolio it all boils down to how persistent that investor is in his Bitcoin accumulation, there some folks that have been in this forum since 2021 earning through campaigns when Bitcoin price was still in the range of $20k , imagine you been paid $50 weekly then that would be 0.0025 BTC and that folks kept accumulating using is weekly pay without scraping a dime from it while he focus on his main business that help him handle his basic needs . Such folk would be able to gather such amount of Bitcoin over time , same goes for those that just started, your campaign earning can serve as a good DCAing , while you take care of your basic needs with your other or main source .
Every investor is different, sometimes they can buy 10 btc at once and sometimes they can buy 1 btc at once and there are also those who buy gradually to reach 1 Btc. It all depends on the financial aspect of each investor because investors are also included in 3 categories, some are rich, middle class and some are simple.
Buying gradually is also not wrong because if the main target is for 1 btc they can start $50 routinely every day for a duration of 5 years if associated with a price of $90k. However, if they start with $50 every week they need 35 years to reach 1 btc at a price of $90k. But the price of bitcoin is not always the same so it's better to just start and buy routinely.