Yes, there are around 8000 unqualified, uncertificated, unlicensed individuals doing there own maintenance / building there own aircraft. We have to get it checked at critical points by an enthusiast inspector, but we do the work. My running costs are about 1/3 of what I used to pay for an AA5B. Do not fee too sorry for us, we are having lots of fun!
Building your own airplane and maintaining it is one thing, as you're the aircraft manufacturer, and are entitled.
Maintaining a certified aircraft, on the other hand, without qualification is another matter entirely.