the fact that people used to buy whole BTC for a few dollars does not change the design it should shows how early they were. but today buying bits of BTC does not mean it is wrong or against Satoshi intent. value grows and access adjust that's part of the Bitcoin's journey.
The more the demand for Bitcoin increases, the more the price of Bitcoin will increase, just by guessing with this plan will not work. As the price of Bitcoin increases, it is important for you to have Bitcoin for your future security, because if you do not have Bitcoin deposited, then if the price of your Bitcoin increases and decreases, you will not have any profit. So for this, you must plan to invest in Bitcoin and if you do not have enough, then by using the DCA method, you plan your future and participate in Bitcoin investment according to the backward method. Because until you have one Bitcoin amount deposited, you continue the DCA method.