In a way with how expansive the internet is you can get the same results by sourcing that yourself. For example, regarding your first 2 paragraphs, you get thos

In a way with how expansive the internet is you can get the same results by sourcing that yourself. For example, regarding your first 2 paragraphs, you get those kind of results by posting 'Show HN: ' threads to get assessment and constructive criticism on your product or business. Additionally you are getting a varied response from people all over the world and at all different experience levels and perspectives. However where online environments are still lacking but getting better is networking. Although places like this are a little better than trying to go on reddit for networking and business advice for example. More transparency behind who is behind the words will usually net better results in that regard.