It’s a consistent pattern at most companies: High-value data and corporate memory are stored in isolated channels on disparate systems. Old processes are protected by those who have been their the longest. The problem is, the DNA of the company becomes lost as long-time employees depart, making it difficult for new hires to find what is available, why decisions were made, and who they can look to for answers. 
Michael Lewis talks about this in his podcast, “https://podcasts.apple.com/us/podcast/episode-1-six-levels-down/id1455379351?i=1000555532510 (Against the Rules)” in the series “Six Levels Down”. When he was looking for someone who actually understood how the insurance industry processes claims and what all the obfuscated code numbers meant, and how doctors actually get claims paid, he had to go six levels deep, to an overworked expert, toiling away down in the hospital basement. She actually knew what all that gobble-di-goop meant. 
Ashley Wolf, Open Source Program Office Lead at GitHub, has confronted this dilemma throughout her career. Not only can there be missing documentation for existing processes, there is pushback when it came to phasing out outdated processes and tooling.