[ben_jones]

Two questions:

Wouldn't a "full" RDBMS like Mysql/Postgres offer a ton of benefits over SQLite (like the features to handle edge cases as they arise) to the point where, even if SQLite would work, SQLite still wouldn't be the ideal choice?

Does wordpress completely abstract the database or do third-party plugins use their own interfaces to the database, in which case a migration to SQLite would break a lot of them?

[dietrichepp]

Wordpress does not abstract the database, so migration to SQLite would break tons of plugins.

Wordpress is also a PHP application, and it's common to have multiple PHP processes running in parallel, which makes it much harder to use SQLite.

[spilk]

Wordpress does attempt some abstraction of the database via its various wrapper classes/functions like wpdb, WP_Query, etc. It's definitely not ORM-level abstraction by any stretch of the imagination, though.