This comes across as a 100% vibe-coded system that could really just be a table or two in a standard SQL database with some care taken with indexing and partitioning (when you reach that point).
What am I missing? What would compel someone to abandon a battle tested system like PSQL for a critical storage engine for this?
You can do an append-only table like this in any SQL database. You can use composite keys to achieve the query+natural sorting abilities over a single field. The effort to replicate this feature in any other environment is so minimal that it the 'vendor lock-in' makes this a non-starter in my eyes.
What am I missing? What would compel someone to abandon a battle tested system like PSQL for a critical storage engine for this?
You can do an append-only table like this in any SQL database. You can use composite keys to achieve the query+natural sorting abilities over a single field. The effort to replicate this feature in any other environment is so minimal that it the 'vendor lock-in' makes this a non-starter in my eyes.