I don't know the original context this is spawned off so may be misunderstanding.
In my work (school IT) these days most school staff have laptops setup with a 2-300 GB SSD that they don't even have direct access to, its just OS, App installs & local profile/cache, Home folders & bulk storage on User/Shared Onedrive or Google Drive.
Students are either BYOD Windows devices or Chromebooks with their classwork on Onedrive/Google Drive too.
A bunch of schools even don't have onsite servers anymore.
A lot of home/consumer users don't need any real bulk storage either: bulk stuff like personal photos/videos are on their phones &/or synced to cloud storage/social media, music & video streamed.
So for a very big number of users a 250-500GB of SSD would cost sod-all and be more than most people actually need.
I've been thinking there could be some kind of open-standard done where Mobos would be built with an onboard OS SSD with some min-standard (M.2 PCIE3/4 interface but onboard & say 250GB would be only a few chips) & would be able to have Win/Linux/SteamOS/ChromeOS etc installed on it.
I also imagine a high-end version where its phase-change/magnetic NVM and some new interface so that the OS actually directly runs off it without using RAM.
Then for ppl who do actually need/want local bulk storage you have normal M.2/SATA etc & its important that this stuff remains available.
I'm a bit weird and don't really trust cloud stuff to still be available indefinitely/when I really need it, so having run out of SATA ports (including a PCIE addon-card) I've just bought a 4TB SATA SSD (all the games!
) , another double-digit TB spinny disk & a small home NAS to put 'retired' spinny drives in