[Question] What’s causing mentorship bottlenecks?

It seems to me like many organizations are trying to provide mentorship to new EAs, but are unable to mentor many of the applicants, even ones that may be qualified. This seems fairly unusual, even by the standards of (for instance) graduate schools, which tend to be just as selective as EA-focused mentorship programs, but offer more extensive mentorship.

Therefore, it seems to me like there must be some sort of bottleneck in the EA mentorship pipeline, which is confusing to me, given how much money is being directed into community building, and given how important this area is under the community-building umbrella.

What might be causing these bottlenecks, and how might we fix them?