Earlier quoted context omitted.
It doesn't seem like there are enough experienced software engineers, at least in certain fields. Native mobile seems to be a tight market. Getting your foot in the door is hard though. Nobody wants to hire a junior.
Why don't they hire a react native developer and train them up on swift or kotlin?
As far as hiring goes there's no such thing as a generalist who can learn the specifics, there are people like that but the industry refuses to recognize this for the most part. The current practice is to prove yourself first by doing open source or projects. A few very brilliant engineers are given leeway based on reputation.