I think many people just want to get the most profit out of their miner.
I am in for the long run but early december I had a chance of getting a miner and all I think about was how can I roi as soon as possible and not about enhancing bitcoin security.
There need to be an incentive for bitcoin decentralization. Cheaper miner with p2pool contract for example if the manufacturers are willing, or plug and hash p2pool miner for people who is not tech-savvy. Manufacturers could play a role in the decentralization of bitcoin, and they should, they are getting a lot of money from the success of bitcoin.

For the short term, I think convincing miners into going to smaller pool is a priority before p2pool matures either through incentives or education of bitcoin security. ghash.io already has 1/3 of the global hashrate and it looks like it is still growing by comparing 24hr chart with 4 days chart https://blockchain.info/pools