I oppose that because there are legacy products, (like the brick pi, grove pi, etc.), on platforms other than the Pi-4 and 5, that can/should use Raspbian for Robots in order to use the published instructions. However I entirely agree that it should be made obvious that Raspbian for Robots is depreciated and support will be extremely limited.
Building the Grove/Brick-Pi over a “naked” operating system isn’t documented anywhere, (AFAIK), and the ability to build it over Buster, Bullseye, or Bookworm is uncharted territory and very likely won’t work.
I entirely agree with removing all references to Dexter O/S as it really doesn’t have any useful applications anymore.
It should also be noted that the “Read The Docs” documentation has a lot of stale data throughout it and should be cleaned up as well.
However, even excluding the other products, GoPiGo-3 isn’t the only GoPiGo out there - GoPiGo-2 robots appear occasionally and there is no separate repo for them, (AFAIK). Since they cannot use the GoPiGo O/S, or the current GoPiGo libraries, (which are specific for the GoPiGo-3), to even build their own spin, there needs to be a way for them to get the software they need.
My recommendation, (after reading your post and doing some additional thinking), is:
Keep the majority of the readme as it is.[1]
Create a separate section for legacy software, with the note that this is intended for earlier versions of the GoPiGo robot.
Within the legacy software section, provide links to RFR and Dexter O/S, with the caveat, (in bold face), that these software versions are depreciated, support will be EXTREMELY limited, and is only available on the forums, if at all.
Translation: If we can help, we will - however that’s unlikely and if we can’t, it just stinks being you.
There should be a note that earlier versions of the GoPiGo robot are also depreciated and any support options will be extremely limited.
There should be a strong suggestion to upgrade to the latest GoPiGo-3 robot, (with a link to the “buy” page), since that will provide the best experience and is fully supported.
========== Footnotes ==========
It should be made clearer which download and installation options, especially the “install on your own software image” and the venv installation procedure, which - if any - require an installation of the sensors libraries as well.
As it is currently written, it appears that the “spin your own” installations do NOT require the sensor libraries which I believe is false.
I would suggest against a “slash and burn” editorial policy.
IMHO deletions should be specifically justified (except the legacy products).
Instead I would rather see some of the instructions amplified with additional guidance, especially with regard to if the sensor libraries need to be installed within a particular section of the instructions.
