It doesn't feel like a realistic bottleneck. Those programs are typically small relative to what we write these days. There are also in-between languages like DIBOL if someone doesn't want to go all the way.

And for any serious system, this will need so many manually reviewed tests, that the code translation part shouldn't even be the biggest chunk of work.

(Also, from my experiments in translating old software with weird language/hardware, Claude is not even that good at it)