Not exactly. You can prune txs if you don't need to keep them for archiving purposes. But you have to validate the whole blocks to verify your own payments. You

Not exactly. You can prune txs if you don't need to keep them for archiving purposes. But you have to validate the whole blocks to verify your own payments. You cannot selectively validate portions of blocks ("shard blockchain") and still have perfect proofs of validity of payments to you. If every block was capped at 100 Gb and there were miners creating such blocks, then only a handful of companies would be able to validate the blockchain and therefore mine and receive payments. That would reduce censorship-resistance and make the system less decentralized.