Organisations typically divide up responsibilities between different teams, and also between different members of each team.

So, people are using AI to answer questions about tribal knowledge? Is that really the assertion which is being made here? Because I find that hard to believe.

Yes, it can get that bad

Different roles and specialties? Different work history?

So, you have different roles and specialties, but you know for a fact that this person should know the answer to your question. I think we're speaking past each other, because this doesn't make sense to me.

I don't presume that someone will have an answer I'm looking for. I'm pleased when they do, but often I just get breadcrumbs, and I have to solve the puzzle for myself.

I'm not GP, but in research very diverse teams are not uncommon. I'm on a team now in which I'm the embedded software engineer / Android SME and my coworker is the 4G LTE/5G NR SME.

I ask him 4G LTE/5G NR questions all the time. I don't know ahead of time if he'll know the answer, but (1) it'd be a solid bet that he does and (2) it's his responsibility to know it given his role.

If you decided at the outset they're of equal value to a $20/mo AI, lay them off.