This sounds entirely reasonable. A bunch of web sites went the route of having a bunch of smart, reasonable people get together and make something real.

When those grew, they became popular with idiots, with spamming/SEO/astroturf, and/or taken over by extremists in some direction (at which point, everyone else heads for the door). The web sites became cesspools of crap.

I'm fine being excluded if that means HN continue to have high-quality content. If the pre-2008 accounts start falling off, it wouldn't be too hard to find a pool of high-quality contributors from 12 years of comments, upvotes by pre-2008'ers, etc.

Indeed, I wouldn't mind having explicit tiers, even if I am in a lower one.