Makes total sense. I do most of my work on greenfield projects for that reason.

But I think you're right. There's really no low-risk path when you have a poorly tested code base. You can keep letting productivity decline, which guarantees eventual project failure. You can do a giant rewrite, which is hugely risky. Or you can gradually dig yourself out.

There's still risk there, of course. But it's in smaller, more manageable lumps. It seems like the clearly superior path to me.