Many managers don't realize the need for redundancy in their workforce. In technical industries you are taught to have machine/system redundancy to ensure no line interruptions...but there is little attention paid to making sure your workforce has the same redundancy.
To be fair, people redundancy is hard. Not only is hiring them expensive [0], but you also need to find someone that gets along with you, the company and especially their counterpart. Then this person needs to also have similar competencies and even if you have all of those points checked, you still need to get them to share enough so that they can actually replace each other - which is in itself already a hard problem. And, if they get along too well, you might end up in a situation where they leave together.
Engineering redundancy really is a children's play compared to people redundancy.
[0] It's not too much of a problem for large corporations, but small businesses with less than ten people can struggle quite a bit to hire replacements, especially if they don't have the workload for two people right away.
I didn't necessarily mean double the amount of people...but at least have enough cross training that a single person won't cripple your company. I've seen this far too many times that one or two people have too much of the key knowledge for a group and if one or both are all of a sudden gone (for any reason) then the rest of the team is absolutely screwed. Rotating job scopes and responsibilities is one of the best ways to ensure you have knowledge redundancy in my opinion...although depending on the team this may be extremely difficult, but still necessary.
The people problems stay, of course, but larger corporations have the advantage that a) hiring an additional employee is not as big of a financial hit and b) they usually have larger teams, where load balancing tasks or filling in for a missing employee is not as big of an issue. That's what I meant by it is easier for them :)
