ELI5 Steemit content and blockchian size

Hey

Could anyone please ELI5 (explain me like I am five - for non redditors), how does all the content can fit into decentralized blockchain of Steemit? In Bitcoin single block has 1 MB, and debate to enlarge it is already a huge reason of controversy.

I can see how much unique content is produced here. I believe that we are here more productive (in terms of bytes) than people on Facebook, who has a huge databases.

Please, explain me the vision and possible issues!

Thanks in advance :)