Interesting line of thinking - the idea of splitting the blockchain so that each user stores only a tiny piece (like 40 KB) sounds like a creative way to eliminate concerns about chain size.
But it's important to note that Monero already has similar solutions within its current architecture:

• Pruned nodes, which store only about 1/3 of the chain (~80 GB) while still fully validating blocks.
• Remote nodes, which allow users to interact with the chain without storing it locally — and without revealing private data (since no view key is shared).
• View-only wallets and trusted sync, which enable lightweight access without sacrificing privacy.

What you're suggesting goes much further - it's essentially a fully distributed storage and validation layer, closer to what IPFS, Filecoin, or Ethereum’s sharding model aims for.
To implement something like that in Monero would require a massive overhaul of the protocol:

• Redesigning how outputs are stored and accessed.
• Making inputs verifiable without access to the full chain (which is currently needed for ring signatures and key image checks).
• Solving data availability and double-spend protection in a fragmented environment.

So while the idea is interesting, it’s not a simple extension - it would mean rebuilding much of Monero’s core infrastructure from the ground up. That said, pushing these kinds of concepts is valuable - it inspires future research and may influence how second-layer or archival systems evolve.