I agree with your post that I think the DoOO metaphor with RoOO is a bit muddled. You still need room (physically, temporally, emotionally, etc) to write. Whether you write in proprietary software or on a typewriter (like the beautiful one on Audrey’s site), we can to some limited extent say that you own that writing.
However, I think the domain is much closer to a publishing platform than it it is to the room in which you’re writing. Just as early modern and modern writers paid for the privilege of publishing their words for a broader audience, we pay yearly for registration and hosting. We could publish elsewhere and negotiate the costs with traditional publishing houses as Woolf did, or temporarily exchange our work for free publication (wordpress.com or github). I think this conflict over owning a domain is conflating the ownership of the stuff (our words or programs) with the service that allows others to utilize our stuff (the domain).
As for students, I think the DoOO is hugely valuable in that we pay for them to have a platform and hopefully help them understand how to use it. But I think it’s up to them to decide individually if self-publication is a valuable enough service to continue to use once they graduate. I think many students will decide that it’s not worth it to pay to self-publish, but they still own the stuff they produced.