From my time working within an academic environment, I can attest this is absolutely true. Especially since the gatekeepers (older professors, etc) have a general interest to see these older articles cited more and referenced. It's not malicious, it's just a fact of how these things work. It's also why the general public's knowledge of how science works needs to be adjusted. Science is not a "100% correct" or "100% not correct" thing, and unfortunately I've seen too many institutions and individuals use that myth to try and push an agenda.
It's a combination of institutional momentum, combined with the fact that a specific narrative is politically expedient. The unfortunate thing is bad decisions, made off of bad science, regardless of the reasons external to the science, generally lead to bad outcomes.