You're making the mistake that because there are differing forces (sometimes seemingly conflicting) acting upon individuals and society, that it disproves anything I said. I hope you understand that just because I didn't mention every single force acting upon us, that I don't know they exist, or that I intentionally ignore them. Just because something exists, or happened, doesn't mean it was right. To suggest otherwise is logically fallacious.

Merit as a foundational principle of society is a necessary requirement for society to exist. On the small scale close to nature (no insulating forces), this plays out almost immediately. This is why the weak and stupid don't survive long in the wilderness, and the intelligent are more likely to survive and procreate. This is highlighted more in the early stages of human development. However, the more information that is amassed, the more traditions that are formed around accounting for what works (and what doesn't), the bigger society gets, the more social welfare programs are instituted, the more friends and family that are around to provide support, the more technology that is invented to make what was previously hard now easy, the more businesses that pop up providing services and increasing efficiency, the more insulated we get from our mistakes, the less merit plays a role in the usually immediate reprisal of nature when people act against what is true.

In this way, what you say is partially correct. Merit, seemingly, means less now than what it did earlier in human history, and less so in the large scale than the small. However, the more negative forces that act against necessary meritocracy (affirmative action, race and gender quotas, feminism, destruction of traditions, disregarding philosophical truths, embracing life over truth, prioritizing what feels good rather than what is right, dysgenics programs like welfare, etc.), the less efficient a community becomes (regardless of size), and if the cumulative effects of the negative forces is great enough, or their negative effects degrade the community for long enough, the community will absolutely fail. This can play out in multiple ways. Either the community completely dies out (doesn't happen much nowadays), or is conquered by a stronger competing community, or a competing community (which doesn't make as many mistakes, is closer to truth, is more meritorious, is more efficient, is more stable, better able to achieve, for its constituents and as a whole) overshadows it to the point of effectively conquering it. It can also play out within a society without it dying or being conquered, where people, families, governments, philosophies, businesses, traditions, morals, etc. that are closer to truth can replace those that aren't. Why do you think modern society is failing? It's because we're moving away from that which is true, and embracing things that are wrong. Abandoning merit is only one of the foundational philosophical principles we've abandoned.

Everything you mention in the latter part of your comment is trying to point out the existence of negative forces, or the fact that mistakes were made and didn't mean immediate failure and destruction, in an attempt to disprove what I said, which again, is logically fallacious. Just because people made mistakes, in the past or the present, doesn't mean that it wasn't a mistake.