For me it's all about familiarity. I have never owned a drilled tank, never even had sump parts in my hands before (the hoses and plumbing etc.) and before this weekend the biggest tank I have owned was a 55 gallon. I don't feel comfortable doing what you described because right now with just a basic sump install I don't feel comfortable.
For example, it's like explaining to the average Joe how to install watercooling on your CPU, GPUs (SLI or Crossfire setup), northbridge and HD's. For me I could do that all in under 2 hours without breaking a sweat. But for someone who hasn't even opened their computer case before and doesn't even know half the of the terminology I just used it can be a bit intimidating.
And yes I have been doing some reading on sumps and how to set it up but I still don't feel as comfortable as I would like because I am the type of person that learns by doing. I know some people can read some directions and go from there - wish I was one of those people.