Having been around that particular block in Ruby, and seen similar things happen in other languages, I'd say that the primary problem with them isn't that the interpreters or basic tech makes it difficult. It's that the community rallies round ways of doing things that don't focus on the "uberbinary" story, and the knowledge of how to do that sort of thing is not well distributed.

For instance, it's not particularly hard to wrap everything from the app down to the ruby interpreter in a single directory that you can then drop into a .deb, but because deployment stories in the Ruby community, from at least Capistrano onwards, focused on getting the app code onto the server and then working from there, with all the problems that entails, the folk knowledge of how to do it just never spread that far. You had commonplace craziness like using RVM to install Ruby on the production servers because it was convenient, and once that mindset was embedded, the community as a whole (and I'm tarring with a very broad brush here, but it's not inaccurate) ignored simpler solutions that worked better, and didn't need tooling with as many points of failure. Bundler is another case in point: you just don't need it in production. Or at least, I never found it necessary past the build pipeline, and I think a lot of folk never found out whether they did or not.

The point is, a lot of the apparent deployment difficulty in interpreted languages is entirely incidental and self-inflicted. Now, there is a real argument that Docker removes the need to learn all the ecosystem-specific folk knowledge you need to get to a point where you can do painless, sensible deployments in a new environment, but I think it's just moving the problem around.