Removing the heroes
In organisations that have grown it is natural for a few staff members to fully understand systems and largely know the company inside and out. In this scenario it is faster to go to them with questions as you know they will have the answer.
The problem lies in the fact this is not a scalable approach. Even if asking the hero in your team works - they only have a set number of hours per day and this limit is easy reached.
A typical scenario for the hero is burnout - they take it upon themselves to try to answer every question, fix every issue. The team become reliant on this person knowing everything. And when this hero leaves (it is only a matter of time) the size of the knowledge gap becomes clear.
Not holding out for a hero
The solution is to get the information, systems and ways of working out of the hero and into well documented systems and processes. Any team member should be able to go on holiday and everything should continue as normal.
A fast and easy way to do this is to get staff members to record themselves as they do specialist activities, describing along the way what and why they are doing it. This creates little distraction (as they were going to do it anyway) and does not require the burden of formal write ups. It is a simple first step to documenting. As the next person comes along to use this, they will write down the steps and add anything that is missing. Continuing this approach will lead to documentation that has been continually updated until there is no ambiguity left.
Bottlenecks in teams reduces the leverage you get from having multiple members of staff. If everyone needs to go to a hero to find information you have gained little from having multiple members of staff.
Sorry Bonnie, we are not holding out for a hero here.