If you search GitHub, you can find thousands of archived go repositories without a deprecation notice: https://github.com/search?q=path%3A%2Fgo%5C.mod%24%2F+AND+%28NOT+is%3Afork%29+AND+is%3Aarchived&type=code.
My search query: path:/go\.mod$/ AND (NOT is:fork) AND is:archived

Most of these packages are obsolete and should be deprecated. To deprecate them properly, the authors need to update their go.mod file and release a new version. It is not possible for archived repositories to be updated unless you unarchive them.

How do you think, should go proxies and go get/list mark modules from archived repositories deprecated automatically?