Honestly I found the multiple versions approach more complex, confusing and more hacky. A virtualenv is just “node_modules” that also contains a Python executable.

It’s a directory - you delete and create them at will, fast, and don’t worry or care about the system Python. Having some crazy setup that patches “require” to handle concurrently installed package versions seems insane, especially if you cannot actually use them concurrently in the same Ruby process. So, segmenting them by project (aka virtualenv) seems like the best solution.