I’m quite certain that when I first encountered product managers working with software teams I didn’t really appreciate the value they brought. I certainly did appreciate the people themselves—they provided a clear vision for the team, inspired them, and very often performed small miracles with stakeholders. But while I was impressed by the people, I don’t think I understood the discipline.
For some time after those first encounters, what I most valued was the stakeholder management. So many teams I worked with had so many stakeholders, and inevitably those stakeholders had conflicting and occasionally unrealistic wishes for what the teams might build. Product managers were the ones who listened to them all, assessed the market and the business, and brought people together in one direction that was clear and coherent.
But today I also appreciate the work of product managers for taking the long term view.
Too many teams are required to work only with a project focus—working to a deadline, needing to tick off features, and with no plan beyond that. In such a situation there is little motivation to consider security, maintainability, and other factors which might make life better in the future.
Good product managers take responsibility for the whole product—not just the features, but everything that makes up its success, now and in the future. Value and market relevance is part of this, of course. But so is security, because a compromised product is less valuable and consumes additional time to fix. Maintainability is essential, otherwise adding new features is both costly and slow. Performance is important because that’s part of the user experience. And so on.
In the past it was mostly only software engineers who cared about these non-functional requirements. Thanks to the rise of product management, software engineers now have influential allies.
niksilver.com 
Interesting perspective – our experiences differ significantly!
> working to a deadline, needing to tick off features, and with no plan beyond that
These are the behaviours I have observed in >10 different product management groups
> take responsibility for the whole product… security, maintainability, performance
These have been qualities I have seen championed by the engineering teams not by product management
> software engineers now have influential allies
I’m looking forward to experiencing this
That’s a disappointing experience. What I didn’t say was that product managers do have to balance the non-functional requirements with other demands – so it wouldn’t be the case that, say, security enhancements always win out to more features. But they should be actively considering those things, and (if the definition of product management fits to what I expect it to be) then they are responsible for their success, or otherwise, there.
Yes that is what I expect of the role too. Unfortunately my experience has been that such tradeoffs are not surfaced or taken, but rather unilateral prioritization decisions are made that are biased towards “looking good” rather than medium to long term product success. The majority of product management functions I have experienced in the past 10+ years have been internally focused task masters rather than allies that provide additional context to create a more balanced delivery.