Exactly. Nothing stops your writing a high-performance parallel database in TypeScript today. Given that runtimes and tooling are actually pretty good, I think TypeScript is actually a fine choice of language for the task.

The only thing you can't do with JS today is share a heap across threads. You have SharedArrayBuffer. You have atomics. You don't need a shared address space.

There's a high performance database called "PostgreSQL" you may have heard about. It doesn't use threads. It uses separate processes and shared memory: just like standard JavaScript, with its service workers and SharedArrayBuffer.

If not sharing an address space is good enough for PostgreSQL, it's good enough for your TypeScript database.

The problem with shared-everything, unmarked, preemptive-parallel concurrency is that 90% of the time it gets used by people who don't know they shouldn't.