If you mark something as 'Not Secure' you're effectively telling users not to access it. It doesn't matter in practice if the content is still accessible when the browser tells people that accessing it is dangerous.
A lot of content that exists on the unmaintained web is going to effectively be lost, and maybe that's okay because the benefits are worth it, but that's the argument that needs to be made.
A lot of content that exists on the unmaintained web is going to effectively be lost, and maybe that's okay because the benefits are worth it, but that's the argument that needs to be made.