To what extent should a product manager be concerned about the portfolio? Is there a portfolio product manager role?
There are portfolio manager roles, but all product managers share responsibilities for the portfolio. Two things: 1) there are incremental enhancements you make to your products for purposes of customer retention and 2) there are enhancements you make to your products in conjunction with other products to form integrated solutions.
The latter is more critical to improving the value the portfolio, because in B2B, the multi-product solutions are the ones with higher value and more conducive to growth vs. customer retention.
So even though it may be the job of a portfolio manager to steer the direction of the overall portfolio (define the higher-value solutions), input from product managers is key to that direction. It’s even more important to the coordinated execution of the overall portfolio strategy.
Create two buckets for your key product priorities – one for things that only improve the value of the product, and the other for things that complement other products and improve the value of the portfolio. It will help you keep everything in big-picture perspective.