As long as companies keep expecting experience in very specific technologies (only at work—400 hours on a hobby codebase don't count for as much as 40 hours writing something at a job for determining competence in a language or framework or whatever, it seems) this will keep happening. It's really, really dumb, but there's little other choice for folks who want to keep their skills (=the names of tools & languages they've used to write something for pay) up to date (=trendy high-paying buzzword compliant).
Doubly true if you're not all-in on one of the major Bigcorp silos (Java, C#).
At a previous job I worked with someone who didn't see a buzzword they didn't like. Since nobody was stopping them, they designed an incredibly convoluted system using all the latest tech. In the end we replaced it with a JVM server and a Postgres database.
I occasionally check their LinkedIn and they're still spending 12-15 months every time at companies, being CTO or Big Data Strategist or whatever.
anecdata but I've only had terrible experiences with companies looking for specific technologies (e.g. a job listing of "$LANGUAGE Developer").
Mostly good experiences when it's a specialist gig that happens to require a specific technology. Like some parts of a stack aren't interchangeable and aren't easy to pick up overnight.
