[drdaeman]

I don't think that's completely true. A good developer must have a good knowledge of the stack he's working on. So he should be capable of managing that stack, shall the necessity arise.

However, it's obviously better to separate matters and offload management/administration tasks to a separate team/person. Thus, a good developer in a good company (which has a separate sysadmin roles) indeed can't really replace good sysadmin because the latter has niche practical knowledge on handling various situations (especially emergencies) quickly.

Nonetheless, one can be both a good developer and a good sysadmin at the same time.

[beat]

You're saying "good developer". What if not all your developers are good? Remember, someone is employing the bottom half of the bell curve, and making money with them.

[sokoloff]

In a lot of cases, they're making money despite them, not because of them.

I suspect in most mid and large sized companies that the top 10% of developers are creating more value than the next 50%, and that below that, the value could easily be negative.