I think an online personal file storage system would be great to have. But the way Google Drive and proton drive work is not good. They are designed to let the company control such files. I think we need a new take that gives more control to users. A private blossom server, where you can have decrypted files for yourself could be a simpler start. If it is not about sharing access to them, all it needs to do is to sync between devices. If it is about sharing access or even enable collaboration (allowing friends to save into your space), then I would say that it is a different solution and it might be a different app just for that.
Discussion
Sharing write access is not the only hard part, sharing read access in scalable and UX friendly way is also insanely hard and this "Blossom is fine" won't magically make it fine.
You can't achieve all this client side. You can't build all these features with only the feature set that Blossom provides... the server needs to understand the format you are using to manage this encrypted filesystem to be able do important tasks like storage reclamation and access denial even for things that are encrypted.
I never said we need to build things like Google, I only said Blossom won't cut it, the full access control of read and write and managing that with filesystem semantics in a UX friendly way is hard work that is inherently complex yet I insist it is necessary for most applications and without it you don't have an open cloud platform.
I am not sure what is the disagreement here. My best guess is that you think you can build this on Blossom, I disagree.