You can have a directory per environment and a directory of shared resources that are used by all environments.
It seems like workspaces add a new construct to be learned and another thing to add to all commands without much benefit. Could we just stick with the simple way of doing this?
I agree it isn't a simplest way to do that, but I don't think that it add as much complexity this. Perhaps it could be more laborious for the point of view of architecture, but it could be easier to handle and maintain.
It's a pretty classic separation of code and config. Might not be intuitive to everyone I guess, but that separation is very beneficial I find.
For instance, adding a new environment is relatively trivial. Not something you do all the time granted, but I have had the need on occasions.
Same goes for removing an environment.
Things like terragrunt can be really helpful. I don’t use terraform without it.