Note I didn't say one person does it all. The question was whether or not the person was familiar enough with all of the types of work to be useful across-the-board (even if they weren't an expert in all of those areas).
Even on a skyscraper, you can bet that all the senior folks there understand the basics of most all of the jobs involved. You don't work in construction without understanding the job in general. This is opposed to IT, where it can be common to hide away in some sub-area and never have experience watching and helping other folks do their work. In many large orgs, the vast majority of developers couldn't build a plain-jane web app from scratch. That's pretty whack.
Even on a skyscraper, you can bet that all the senior folks there understand the basics of most all of the jobs involved. You don't work in construction without understanding the job in general. This is opposed to IT, where it can be common to hide away in some sub-area and never have experience watching and helping other folks do their work. In many large orgs, the vast majority of developers couldn't build a plain-jane web app from scratch. That's pretty whack.