I'm not totally convinced tracking/data mining is the key distinction here. I'm going to assume your dozen users are friends/family and 'well behaved'. Global cloud services do not have that luxury. They have to deal with wide ranging usage, sophisticated attacks, bots etc that you simply don't have to deal with.

In short, they have a vast set of requirements you don't have, each one of which adds complexity.

Dont get me wrong, I definitely agree with your message. However I think we need to be clear that a raspberry pi running some services is not the equivalent of cloud services without 'advertising, tracking etc'