I think you refer to pruned node, which download whole blockchain but only store some latest blocks and UTXO set (which necessary for verification purpose). People already can run pruned node since some years ago using Bitcoin Core software.
You know ABC, basically just think we need this brainstorming to meet more and more "Core Wallets" out there among BTC hodlers, instead of hardware and SPV wallets. [1] so prune nodes are very close to the concept if they save ALL unspent transactions (non-oxidized transactions) - which amazingly this could also provide compatibility with GDPR principles in future.
I do also follow ideas like assumeUTXO which shows us there are still some sort of improvements neeed to get considered [2] now look at this oxidation fee how forces the entire network and hodlers to achieve better performance of prune-nodes in bitcoin blockchian and facilitate ideas like assumeUTXO.
[1]
https://coinguides.org/bitcoin-blockchain-pruning/[2]
https://protos.com/bitcoin-core-developer-proposes-new-type-of-pruned-node/