If. you look at Product Management in other industries, CPG, Pharma, Consumer Tech etc, Product Management (or sometimes Brand Management) is primarily a business function or business/marketing function.

It's only in software and related fields that Product Management is tied VERY closely defining what to build. That's not a bad thing in itself, as the nature of software products is very different from those other industries.

Software is more fluid and the use cases evolve more quickly etc. So there is a need for a tighter relationship between what we build and the ongoing market needs. The issue though is that that has become the dominant focus of how a LOT of companies define Product Management. I see a number of reasons.

1. In the very early stages, building is the primary focus. i.e. understand some market need and build to suit it and figure out the business aspects over time. This is the reverse of physical products where real manufacturing and distribution costs need to be defined up front with an understanding of market demand.

2. That initial, focus on the build role becomes the defining aspect of the role. i.e. as the business matures, the role of PMs doesn't mature along with it.

3. There's a broad cultural focus on building -whether it is Agile or Lean Startup etc on building something. I once asked Scott Cook (Intuit founder) why more companies didn't emulate Intuit's market and customer focused approach - he said it was because unlike himself who came from Product Management (at P&G), a lot of startup founders are engineers and thus their inclination and talent is building first.

I'm sure there are other reason, but in short, a lack of understanding of what Product Management is, along with strong tech culture bias toward build (Agile, Lean Startup etc.) has lead us here.