I think that EBS is the difficult engineering problem that they purchased instead of built from scratch here. Writing binary records to a file and reading them

I think that EBS is the difficult engineering problem that they purchased instead of built from scratch here. Writing binary records to a file and reading them all into memory is not going to be a time sink that prevents you from finding product/market fit. The $120,000/year burn rate on Aurora they had seems alarming; an alarm that strongly implies "we didn't use the right system for this problem". My guess for "why didn't they use something off the shelf" is that no existing software would be satisfied with the tradeoffs they made here. Nobody else wants this.