It mistake misses the point of the investment. The pay-off is experience in new patterns, new tooling, new approaches. The dividend is in the job where you use the tool but the capital gain is in experience.
When I hire for my team, I never mention the stack. I don't care. I am hiring software engineers, and what I value is mindset and ability.
I'll throw you in at the deep end. Learn the language, libs, tooling, infra on the job and the team will support you. Because you're awesome. That's why I hired you.
That sounds crazy to me. If you throw me at a new language, sure learning the language might only take a couple of weeks (if it doesn't radically depart from what I already know), but learning the libraries/ecosystem is at least 6 months. Probably more for something yuge like Java or .NET.
I'll be referencing the doc and tinkering every little thing for many many months, which is sure to affect my productivity. Append to a file? Make an HTTP connection? Serialize a data structure? Have to look it up.
Then come all the 3rd party libraries a seasoned developer will already know. How do I talk to Postgres? Which of these five 3rd party libraries should I use? Which library do I need to help generate my SQL statements?
It's like you're looking for a journalist for an American newspaper, and you decide "oh, you don't have to speak english, you can learn that later". Sure, you can do this for an exceptional talent, but on average you're better off finding people who already speak english.
At our company, out of the 8 engineers I hired, only 2 had specific experience with our backend (Elixir) or frontend (Flutter) stack. I hired for apparence of talent, experience in some other equivalent stack and the right attitude towards learning.
All of them got productive rather quickly and had PRs shipping to prod in the same week, if not within a couple days.
I’m not saying it _will_ go as smoothly for anyone else, but if you have the right environment and pick the right people, as an employer you’re better off being flexible with experience.
When I hire for my team, I never mention the stack. I don't care. I am hiring software engineers, and what I value is mindset and ability.
I'll throw you in at the deep end. Learn the language, libs, tooling, infra on the job and the team will support you. Because you're awesome. That's why I hired you.
edit: Sound _less_ unintionally arrogant.