Kysely was inspired by Knex, but took a more predictable route instead of providing generic APIs that produce different SQL for different dialects. We believe that dialect "lock-in" should never be a real concern because migrating from let's say, MySQL to PostgreSQL is extremely rare in the real world.

That's true, I agree.

But we are mainly targeting software editors that build data analytics platform and let their customers choose where they want to store their data and run their analysis (on premise, in the cloud). Having a common API avoid adapting developed applications for each customer.