An average monero tx is 2.5 kilobytes, and has dynamic block sizes that expand during periods of high volume of txs and then contract again. Nodes can be pruned to 1/3 of the full size.
The largest single possible bitcoin transaction is 4 megabytes which takes up an entire block and includes a jpeg which is stored on full nodes and has to be verified by all users.
The problem (at least w.r.t. scaling) is not the size of the historical chain, it's the size of the state, which must be maintained in order to prevent double spending.
reply