Absolutely everyone who doesn't work with hardware, or on specific problems, because it's far more popular, easy to hire for, easy to deliver an MVP with and easy to have people jump between frontend and backend with. I'm saying this as someone who specialized in .NET before and now writes Node/TS. I simply grew out of the opinion that language/architecture is everything. When you make a product delivering quicker matters more than choosing a marginally more performant language, unless you're solving a very specific problem that requires that performance. Adding one more server costs less than hiring engineer for a more niche language and if you have the success that requires you to scale up that much, money is probably not the problem anymore. Granted we're in LLM era where everyone can write anything but it's still better to have people vibe in language they actually know, so they understand what's happening. You can always extract services later on and rewrite them in a more performant way, noone's stopping you.