about duplicates - google has this thing called grants https://bughunters.google.com/about/rules/5479188746993664 that pay people for doing security research, even if they don't find any bugs. we agree that doing security research is valuable even if no bugs are fixed.
about having access to private bugs, we don't want to share vulnerabilities with others without the researcher's permission, but the original researcher can make bugs public on the new website, you can see some of them here https://bughunters.google.com/report/reports
about having access to private bugs, we don't want to share vulnerabilities with others without the researcher's permission, but the original researcher can make bugs public on the new website, you can see some of them here https://bughunters.google.com/report/reports