None of these things are a concern on traditional social networks. They have to be solved before the world has any chance of moving to a decentralized network.
I say no. Most of them don't have to be solved first.
Feel free to convince me that 3 days of downtime on my personal messaging account cannot have my personal account is a problem.
https://www.theguardian.com/technology/blog/2010/feb/11/face...
These are people who typed "Facebook Login" into a Google search, clicked the first result without reading, and got confused. Now tell these same users that Comcast blocked their social network or that they can't log in on their phone because their home Internet connection is down.
If you want a social network filled with just people like you and me, look at App.net or GNU Social for inspiration. If you want average users to sign in, these issues absolutely do have to be solved.
The early web (when I entered and before) wasn't for everyone. And thats OK for me. Actually I think it is a good way to start.
It got where it went by doing the opposite of what you're suggesting. The walled garden for smart elites were mostly working on OSI from what old timers tell me. The TCP/IP, SMTP, etc involved lots of hackers trying to avoid doing too much work. Much like the users you prefer to filter. Then, it just went from there getting bigger and bigger due to low barrier of entry. Tons of economic benefits and business models followed. Now we're talking to each other on it.
If you're internet connection goes down, power goes out, you get DDoS'D this would hinder your ability to use any third party online service anyways. The data cap and ISP restrictive terms of service are a different problem that would be challenged and fixed given internet subscriber would go the p2p self host way. The commercial ISP situation is a terrible mess right now. If you got hacked unplug from network, boot from recovery, restore from backup, you're back online in less time than it takes to recover a hacked facebook account.
You say decentralized but it seems to me you meant distributed here.
One data center * 24 backup generators * 3 MW each = 72 MW per data center. Four of those = 288 MW > 1/4GW.
Google has more than three data centers.
Assuming that they're doubling energy consumption every year they'd have reached 8GW in 2016. That's 8W per user if we assume 1 billion users. Energy usage of a Raspberry is not insignificant relative to even this.
Doing things at scale is vastly more efficient. And only a subset of Google services can be relegated to a Raspberry. Even if you host your own mails, are you ready to ditch the Google search index and Youtube?
[1] http://www.nytimes.com/2011/09/09/technology/google-details-...