Exactly. I often think of scenarios such as this in evolutionary terms. Imagine a doppelgänger competitor in this space, exactly the same, except they're pretty content with their crappy tech ecosystem and focus on delivering features (albeit, more slowly than they might with a more modern system.) And so...

1. You focus on the advice here, adding tests (which IMHO is actually pretty difficult on a legacy poorly architected/documented system), source control, refactoring, etc.... with any time remaining in the schedule devoted to adding features.

2. Your doppelgänger chugs along and releases several more features than you do, giving them a market edge.

What happens next I suppose depends upon what difference those extra features make. If the delta is small, you may be able to pull out ahead, in the long run. But if it's large, then your company may start to lose revenue / customers. Then, the screws will likely tighten even harder, and you'll be forced to sideline refactoring efforts and double down on delivering features. And then those refactoring/cleanup efforts will bit rot and you'll find yourself back roughly where you started, except now you're behind your competitor.

There's a quote I can't seem to find atm that summarizes this. It was something along the lines of "With php our product is already up and gaining market share meanwhile our competitor is still futzing with their rails configurations." (If you know the actual quote I'd love to see it.))