Almost everyone who wants to fundamentally reinvent programming seems to come up with visual dataflow programming, which is strange to me because aren't those just function calls?

No... it's plumbing. Function calls are nested to-do lists. It's a different thing all together.

Flows all have queues.

Function calls (called messages) can go in a queue in the actor model.

I do think dataflow programming might be interesting for low-level if it compiled to hardware as well as C. There's an old project for that here but the actual webpage and docs are gone:

https://github.com/orcc/orcc