Sandstorm is not necessarily about running the server at home (though you can). It's more about being able to choose what is on your server and control how your data is stored and accessed, whether on a home machine or running in a datacenter.

I think I can use apt-get/rpm/etc to control what's on my server already these days?

Sure, but only if all of the following are true:

1) You understand how to use the Unix shell and everything else that goes into maintaining a Unix machine.

2) You have the time to do it. (This is what has always stopped me, FWIW.)

3) You are willing to spend money on a machine that has sufficient resources to be responsive when you use it but sits idle 99% of the time since you're the only user.

These obstacles are what drive people to SaaS, where they no longer have freedom to install arbitrary software.

Unfortunately we lost all of the small independent ISP's that offered any semblance of competition. I just host my own stuff anyway with an ISP known to be pretty relaxed about it. You're right, though, it's a major problem.