To become a Legendary w/ a 2021 registration date by now would mean posting just about every day (or at least 14 times per 2 weeks) since then, along with accumulating an average of ~1 merit every day... No easy feat really. It requires a lot of commitment to going beyond shitposting, which is a step most accounts here aren't willing to take. They are here because its "easy money"... once you have to put effort into it its no longer "easy" anymore. So they will never get beyond Sr. Member or Hero and they don't care.
I think it took me at least 4 years to get to Legendary based on the speed of my posting, which was intermittent. I don't think merits would have been a factor but who knows.
Your analysis provides a valuable perspective on the journey to reach Legendary status. It's important that reaching such a milestone requires consistent dedication and a willingness to contribute meaningfully. If one user honestly wants to reach the targeted figure then it will be possible for him but if users can't gather much knowledge about the forum with current news about the cryptocurrency then obviously the users will fail to reach that figure.