Do the versions of the dependencies that you used no longer exist anywhere?

Fair counter, and that's the right stance. The tax I'm pointing at is the implicit social one: feeling like you owe a response. Plenty of publishers get burned out before they figure out your model.

they exist, but they are likely unmaintained, and may have known security issues.

i have a project that suffers from that. the version of a library it is built with is old and unsecure, but the newer supported version has a completely different API that would require me to rewrite the code that uses the library.

i had a second such case where i discovered a fork of the old version of the library which was still maintained. otherwise there too a rewrite would have been required.

In my experience, the most common problem is that a dependency changes. It drops support for something, API changing, etc. If it's 3 dependencies deep, and one of the deps in the middle isn't maintained anymore, well...