It often doesn't happen. The reasons seem to vary by field. We do see it in a few very hard fields like materials science.
In the softer end of social sciences like anthropology, education or the humanities it's obvious why not: they don't make empirically testable claims about reality anyway so there's nothing to replicate. This is the Arday problem, where he was publishing what they call auto-ethnography: effectively just blog posts about the author's own feelings. He even interviewed himself in the third person.
In the harder social sciences it's because nothing actually builds on anything else (see "A problem in theory" [1]). Psychology and related fields like sociology, criminology, etc are basically just a pile of random ideas pooped out in brainstorming sessions. There are hardly any overarching theories generating testable predictions, so studies test whatever random claims the researcher thinks is interesting enough to get in the news. Everything is just rocks lying on the ground rather than towers of understanding, so when one paper is overturned it has no impact on anything else. Citation counts obscure this fact, but do some reverse-citation checks and you'll find a lot of citations are worthless or outright invalid.
In modeling based fields like economics, epidemiology or climatology, it's because they can't put the thing they study in a lab and do high speed experimentation. "Replication" comes to mean repeating the same analysis on the same data set. Often they literally just run the same program on the same input file, get the same result and call it replicated - or sometimes they call it replicated even if the outputs don't match! See [2]. But the program is just a set of assumptions, not real discoveries, so building more papers on top of that program's output doesn't detect invalidity. It will all replicate in some very narrow technical sense without that proving anything useful.
Sometimes outsiders notice what's happening but over time academia has built up a complex web of lore that protects them psychologically. For example, they routinely reject or ignore feedback from outside their field on the basis that it doesn't come from "experts", meaning themselves, or it comes from "right wing" people, meaning anyone who isn't an academic or close political ally.
[1] https://www.nature.com/articles/s41562-018-0522-1
[2] https://dailysceptic.org/2020/05/06/code-review-of-fergusons...