Let's say that six years ago (that would have had been August 2019), a person had wanted to be very aggressive in his bitcoin investment, and he looked back historically, and he saw that a person who had merely invested 10% to 15% of his income into bitcoin could have had reached a good quantity of bitcoin and even to have had been on his way to reaching overaccumulaton status after a couple of cycles.
At the same time, he realizes that he cannot go back in history, yet he would likely have to be more aggressive if he wants to attempt to be able to do the same thing, so he decided to invest 25% of his income and so he figured that he would have had invested 1 full year of his income into bitcoin after 4 years and a year and a half of his income in 1.5 years.. so he considered that he might be able to get close to overaccumulation status after about 6 years investing.. perhaps? depending on how bitcoin does and if he can stay committed in investing 25% of his income into bitcoin.
Sure, if someone first started investing at least 10% to 15% of their income in bitcoin 6 years ago, they would now have a big holdings, with how much bitcoin price has increased over the years. That person might be in a strong position now, perhaps we may even call it overaccumulation.

But we cannot go back to the past right now, and you're right that if someone wants to reach that level now, they will need to be more serious about their plan. Whether Investing 25% of your income will shows that you are serious, and if we can maintain this level of investment for some years, we may reach the level or even more but that will depend on how bitcoin operates.