enuff of the fluffs, to truly allow users "own" their data we need:
1. store data on their own server or locally on their device
2. store data on a public ledger/storage network with guaranteed data availability, and .. encrypted

This is very different from owning assets where it is sufficient to just own the key

building degencast.wtf /degencast . ex-bitmain, binance

zk tech will do that. also possible with encrypted data stored in distributed systems and shared by request. no serious mass market product will require storage of large quantities of data locally.

because knowing is finding the limits /outercorps

Yes and "no serious mass market product" my android storage stats say otherwise tho. You could easily find apps with >1 GB storage. Encrypted data in distributed system is another route. It is just tricky to make sure the data is available without relying on chains like arweave or filecoin

why not encrypted data on arweave unencrypted for use on the signer’s authority?

people don’t want to be device-bound

Yes and Arweave is a good candidate for this use case and could be a important piece of the puzzle. That said, not all data need to permanently stored, and could be a good complement for long term archive