I agree with the sentiment, but still it is a bit worrying when we see so many hyped startups where a lot of scientists are like "yeah this won't work at all."

I agree with the sentiment, but still it is a bit worrying when we see so many hyped startups where a lot of scientists are like "yeah this won't work at all." I mean I know that there are doubters for good ideas too but what's the line to draw in terms of skepticism?