The idea is that the accountability is at the level of the magazine, not the individual author. It's not the norm today (outside of many newspaper editorials) but doesn't mean there's an inherent problem with it. I'd also observe that, in many/most cases, when organizations like analyst firms put out reports they're widely viewed as the opinion of the firm even if they're bylined. Which isn't unreasonable given that they're presumably peer-reviewed.
In general, bylines have become standard practice because writers, etc. want it. Not because publications and other content producers prefer it that way.
