You provide a good argument.
> but what's the alternative?
The alternative is not to use the device, and/or find a replacement.
That may sound fairly dogmatic, but over the course of a decade or so, its pragmatic value becomes more apparent. If a piece of hardware works with free drivers, it will likely continue working until the magic smoke escapes. With binary blobs this is not a given, as various kernel upgrades (or even user land changes) might break the environment.
I realise that people no longer count the usability of their hardware in decades, but still, there is immense practical value in knowing that the thing you set up to work once will continue doing so allowing you to focus on the task you set it up for without requiring your attention.
This, of course, goes against the use case of chasing for example (graphical) performance through the use of proprietary drivers, but that raises the question of what that performance is used for, and whether these use cases are inherently pragmatic (catering to the newest generation of desktop environments, etc. It might be a good argument that these DE increase productivity for the user, but still, the "pragmatic" argument doesn't fall automatically to one side here).
On a larger collective scale, the long term pragmatic effects of using free drivers over proprietary drivers are not really disputed I think.
As a less technical example (because OS en FS are, as you mentioned, almost indistinguishable there):
Getting off FB is a recurring theme here on HN. Free Software values have always led me to eschew that particular site at the expense of social convenience. As I now read these various stories, I can safely conclude for myself that I indeed made the long term pragmatic choice.
Open Source here doesn't really have anything to say on the matter, where Free Software has always recognised sofware as a social institution as well as a practical tool. As such, it might be easier to recognise any long term detrimental social effects resulting in a long term pragmatic approach for individuals.