[upbeat_general]

Clusters and supercomputers are able to fully control the hardware & OS. environment modules are useful in that setting but do not solve OS differences, not to mention themselves need to be installed/maintained. lots of time developers do not work on your same cluster (say, for any open-source code) and environment differences can be significant.

I regularly use large clusters and even there docker/singularity are very helpful at times (very simple example, glibc requirements).

When you are talking about well-written code that only requires posix (and nothing beyond) and does not interface with hardware, etc. etc. then virtualization seems crazy.