The max blocksize is a code constant, so it requires upgrading software on a lot of machines to a version with the fix, which is incompatible with older version

The max blocksize is a code constant, so it requires upgrading software on a lot of machines to a version with the fix, which is incompatible with older versions. Called a "hard fork", meaning a fork in the blockchain - because older software would see those new larger blocks as invalid. The blocksize has been increased in the past, without major upheaval. There is some risk, but staying with outdated software forever also has its own risk. We should make the single hardfork count - eg. an agreed schedule to increase blocksize over time to keep pace with moores law was proposed as a way to avoid future recurring hardforks. I think the issue is to manage the risk well - telegraph and explain the roadmap so there is certainty for all parties. Gain consensus, but understand perfect consensus is impossible.