as long as the big blockers don't come back to ruin the base layer, I'm not worried about future on-chain growth or the bandwidth required to sync blocks.

it's only when people who don't understand the physics of computer networks try to suggest idiotic things like "giga-meg blocks" that this becomes an issue.

4MB/block per 10 minutes is just 24MB/hour. My personal storage and home network speed have vastly outpaced that for the last 20 years. I just bought a microSD card with 1TB on it!