This doesn't feel like a sustainable way to build engineering org. You only get N chances for such 'juicing', what do you do when you need to juice but don't have open headcount. You have to come up with a strategy for that anyways, so why not implement ' want juice but no headcount' strategy and expand your hiring pool.

I've also found that people who sell themselves as "Rust/SAP/Java engineer" seem to have a huge bias against anything else which makes sense since they've built their careers selling themselves as experts in a particular niche.