My take on it is:
HN/Slashdot commenters can be valuable for pointing out what's technically wrong with the product. They also tend to put too much weight on product's shortcomings. However, they are blind to what's right about the product or discount the product's strengths for the non-geek consumer.
However, that doesn't mean that average consumers are ultimately right either. On the one hand, they don't have the technical understanding which often skews the prediction towards market failure. Their naivete just lets them try the product and vote with their wallets. On the other hand, that lack of knowledge leads to unrealistic hypothetical products... e.g. "if they can put a man on the moon, why can't my smartphone battery last 3 months and project a 4k video with 5000 lumens on my living room wall?" (relevant XKCD: https://xkcd.com/1425/)