The internet is the platform that provides the variety: Hacker News for some topics, and for example RCGroups, SpaceFlightNow, or hundreds of other topical forums for others.
While it is silly to complain about "community X is going downhill", I do miss the old "information bubble" that HN was many years ago. The YC alumnus Reddit has taken over the role of a general link-sharing and discussion on every possible topic platform for every topic - but there is no longer any website (that I know of) focused on the advice, thoughts and discussion of technology startups mostly by founders of technology startups.