There are quite a few complaints about disk space needed to run a full node of the bitcoin blockchain and the time to download the blockchain. Point 7. of the a.m. whitepaper reads:
"7. Reclaiming Disk Space Once the latest transaction in a coin is buried under enough blocks, the spent transactions before it can be discarded to save disk space. To facilitate this without breaking the block's hash, transactions are hashed in a Merkle Tree, with only the root included in the block's hash. Old blocks can then be compacted by stubbing off branches of the tree. The interior hashes do not need to be stored. A block header with no transactions would be about 80 bytes. If we suppose blocks are generated every 10 minutes, 80 bytes * 6 * 24 * 365 = *4.2MB per year*. With computer systems typically selling with 2GB of RAM as of 2008, and Moore's Law predicting current growth of 1.2GB per year, storage should not be a problem even if the block headers must be kept in memory."
Why is this not being implemented to get the required disk space down to almost nothing (about 4.2 MB/year)?
DISCLAIMER: I'm not a programmer, cryptographer or geek, so I don't understand the Merkle Tree and respective analysis/conclusions. Nevertheless it seems clear, that Satoshi Nakamoto did foresee the existing problem and included a solution in the whitepaper.