[bevr1337]

> Shouldn't it be possible to encapsulate something like this with SQLite and produce an accounting engine

Indeed! https://www.gnucash.org/

> that can guarantee consistent numbers

It was consistent, and now it's transparent and user-friendly.

> and generate key numbers

Yes, hledger generates useful reports including trial balance, p&l

[lvass]

FWIW, GnuCash supports multiple backends, sqlite, a couple of popular sql servers, and I believe the default backend is XML.