In a product development cycle, how to get engineering and product management on the same page

As mentioned in the previous post, one of the biggest problems in a product development cycle is the objective of ensuring that the engineering teams and product management are in agreement about the resource commitment. Product Management talks about getting new features in place, while engineering has to content with having to dedicate resources to efforts for handling infrastructural and legacy tasks.
What are some of the tasks that an engineering team has to do which are not related to new feature work:
1. Test features from earlier versions and fix issues in these
2. Incorporate new components - you could be incorporating common components (and once you are building a product, there are many features that can be done by utilizing common components such as disc burning engines, installer technologies such as MSI, Installshield, Visual Studio etc); over a period of time, such components need to be upgraded and there will need to be more testing required
3. Spending dedicated time to improve the quality. Companies with large products such as Microsoft, Apple, Adobe, etc defer a number of bugs in their products. Some of these bugs are deferred since they are not critical, and there is a need to release the products. However, over a period of time, it may turn out that the overall impact of these deferred bugs can be high, and may need to spend some dedicated time to fix these bugs.

Now, what needs to be done in such cases since there needs to be an agreement between the engineering teams and product managers.
First, before starting on a new cycle, the team needs to spend around a week (with multiple meetings) to work through what all is planned for the next cycle, and this includes discussing what needs to be the focus of the release. A good way to sort through the legacy features is to emphasize that legacy features are non-negotiable and need to be tested since they impact customers directly. In a number of cases, without this discussion, the Product Management team has not thought through the need to test legacy features and when this discussion happens, this issue will get cleared.
Secondly, when the discussions about the features for the cycle starts, the team will need to work through setting aside dedicated time for infrastructural items, and the engineering team will need to push a bit hard on this issue; and in most reasonable cases, there will be an agreement between the engineering and the product management team as long as the time needed for this infrastructural work does not take too long.
In all such cases, focusing on a mix of the needed technical architecture work and new features should help to resolve such issues.