At the moment hive blocks are 64kb size. Meaning each block, each 3 seconds we can add a maximum of 64kb data to the chain.

Witnesses can increase/decrease block data if there is a majority, same as for the 20% APR on HBD.

Thing is bigger blocks means bigger chain, and more expensive hardvere to run it. So there needs a balance to be made. The curent block size has been serving well for now and the hive chain is cheap to run. I run a witness node on Hive ... I for sure cant afford to run a node on for example on Solana where you need a dacenter to run it... very exoensive... this makes chains centralized...

The block size was the prime reason for BTC/BCH for back in 2017