I know this is an offensive idea, but you simply have to decide whether to cater for the elites or the lowest common denominator. As time progresses the people just joining now will look back on this time as a golden age of HN -- it will get worse -- and in the future there will be a new wave of lower intelligence HN'ers. That is how it always is.
The solution I would prefer is (1) allowing users to curate their own experience with far greater granularity than allowed on a site such as Reddit. That is, use twitter like ideas of followers and lists. Allow us to choose who we see comments and stories from. I care about the votes from these people much more than somebody who just joined a couple of weeks ago and hasn't programmed or owned a startup company. (2) giving users with popularity in the community, moderation power similar to the kind found on StackOverflow. The power to close topics. Respond to bad usages of the vote button. Respond to flags. Perhaps even the power to moderate comments.