Having been around p2pool for longer than most— I can't agree with your views here. The donation income on P2pool has always been a trivial amount— sure, aggregates sound impressive when you don't realize that most of it was at $10 price levels— and I understand forrestv spent a fair amount buying mining hardware (since vendors have never eagerly tried to work with p2pool).  If someone was contributing substantially I don't have any doubt that forrestv would happily share donations with them.

From my own perspective p2pool exists in something of a design minima— it does everything _I_ want well.  There are some tweaks here or there that I might like (e.g. support for failover to another bitcoind) which don't even reach the level of want for me to go dig into the codebase and to it.   Further development of P2pool would be things like reorganizing the sharechain to support other payout schemes or reduce variance for small miners... this isn't small work that most people are just going to go out in do— I think my experience in bitcoin core tells me that contributors in that space almost don't exist.  For myself I'm perfectly happy with my level of share variance on P2Pool, so I can certantly understand why others aren't rushing in.