Almost, yes, but not quite. Curation and integration by a trusted party is a valuable service, and I very much appreciate Mozilla, Debian and others doing this

Almost, yes, but not quite. Curation and integration by a trusted party is a valuable service, and I very much appreciate Mozilla, Debian and others doing this work and enforcing their inclusion policy, e.g. the Debian Free Software Guidelines and whatever Mozilla's technical review involves. Debian's onerous rules in particular are great for the user – I can rely on packages to be appropriately licensed, to receive security patches without breaking my system with incompatible changes, to be compatible with the rest of the packages in the distribution, etc. Some important differences from "marketplaces" provided by various for-profit companies are 1) the user can choose whatever curator they wish, or opt to install whatever they want at their own risk; 2) the service doesn't usually involve payments, selling, shopping, etc. which would usually be associated with a marketplace.