> Eternal September appears to be universal property of online communities - IMO Reddit has tolerated it better than most thanks to it's ability to fractally segment itself into smaller and smaller communities that don't observe these issues.
I think this is the key - Eternal September doesn't generally impact Reddit as a whole (except for the default or frontpage), but rather it impacts each individual subreddit. However, each subreddit this happens to then goes and makes a new, separate subreddit to essentially start again.
Entropy will still build up in the software, infrastructure (both human and hardware), monetization model ("my highly targeted customer base keeps moving subs, and they have ad-block!") and an accumulation of bad "federal-level" decisions that get made and held reddit-wide. The question is when this will this burden begin to stifle the creation of new "escape subs."
I think this is the key - Eternal September doesn't generally impact Reddit as a whole (except for the default or frontpage), but rather it impacts each individual subreddit. However, each subreddit this happens to then goes and makes a new, separate subreddit to essentially start again.