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.

0260378aef

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. 

03a9f7de67

Bitcoin scaling is a problem as well. Lightning is becoming worse with the network growing, it seems to me. 

Not saying Monero can scale well, but Bitcoin has the same issue so I would not see that as a problem. 

If we can figure out scaling for Bitcoin, maybe it will work for Monero too. 