The first two options only increase throughput. They don't address the system's ability to handle that throughput.


Optimizing transaction size actually improves scalability. The next such major upgrade will probably be the addition of Schnorr signatures, which will drastically lower multi-signature transaction size.

Improving validation and initial sync speed or reducing bandwidth, latency and storage usage also improves scalability because they reduce the costs of increased throughput. Enough improvement in these areas can justify additional block size increases, especially as improving technology makes high speed internet and cheap storage more widely available.