Every time there is some news on some research breakthrough in a technological field, lots of people comment how it is unrealistic, not yet a working product...

Yes, it's research if they had a product they would have founded a company and made lots of money already. I suspect these comments are due to the fact that many here are in software, where an idea can essentially instantly transition from research to production. In hardware that can take decades (and there might be lots of deal breakers discovered along the way).

Now if the complaint is about the press releases reporting on those breakthroughs. That is a problem with the pressure on scientists to work on relevant problems (often strongly called for by the same people who then complain it's not a product yet), and demonstrate impact.