I agree with this point, it seems most people don't get the fact that most of the debugging is happening in the development phase (before building an unikernel)

I agree with this point, it seems most people don't get the fact that most of the debugging is happening in the development phase (before building an unikernel) and when you need to debug in production I think that's certainly not as difficult as it seems. There's no issue with logging through network as opposed to logging to a file that you need to pull to see the contents (containers). It's also common to have a debugging interface over network that you can use to inspect program state (eg. Clojure nREPL, node.js inspector protocol, and this can be built into any environment), I'm pretty sure even Rust can have networked REPL that can satisfy most debugging needs.