This is so true. From a sysadmin perspective, if your stuff isn’t in the repositories available we are not going to deploy your stuff. Sometimes we have to of course, but there is nothing more annoying than something that expects to have internet access and/or uses custom specific versions that are packaged along with the product.
“But it works for me on my laptop”
DeveloperDude 2018
The worse case of this is when the developer has dependencies that are basically the nightly builds of whatever technologies the project uses and expects us to have those in production as well. Not going to happen 
That really does not cut it in a production environment where you want everything to be reproducible. And Docker is not the solution. That would just put your application within a little container I have no insight into, and would require you/us to also add our monitoring platform stuff in there, and so on. And why would this be in a container? I would only use containers for something that is completely stateless and needs to run distributed. If the container would just run “forever” then I would skip Docker entirely and just set it up on the machine directly.