Superseded Items can show in the product structure page in PDM but there is no mechanism PTC provides to extract the information from the tool for reports. The out of the box BOM reports do not even show a item has been superseded. Although I have created a superseded item report from the Part Master this needs you to manually check with your BOM against this report.
"superseded by" is an attribute that you can add to your product structure but there are no entries returned. If this was filled we can then just report a .xls from the product structure page.
Please either update your out of the box BOM reports to highlight a superseded item or provide similar to alternative and substitutes that it may be replaced with "superseded by" part/s or in the product structure ensure the "superseded by" attribute returns a response in the structure. An supersede icon is not sufficient when you need to use the BOM away from PDM and it does return the superseded by items.