Thinking through that very pertinent question out loud is useful, because it exposes the relentless creep of issues that have completely foobarred the housing industry in general, and quick, low cost housing in particular.
There's absolutely nothing technical about getting a living space together that is beyond the capabilities of a modestly handy bunch of people. Tiny houses and caravans are exemplars precisely because they dodge the issues which bedevil the construction of larger spaces. The sorry list commences.
- Five sorts of LBP needed to touch a conventional house: founds, weathertightness, structure, carpentry, roofing. Hiring LBP's does not come cheap even though most of 'em were created by a mail-in form from building trade mags. Equivalent of packing the cert in with the WeetBix....
- working at heights for anything over 2.4, which in practice means everything roof-related plus fall protection. Expect the bill to run $5-15K.
- fencing of site and those 'Sign has Sharp Edges' hazard notices. Expect another $4-8K.
- Electrical and plumbing need certified tradies (the attraction of tiny house 12/24v everything plus cassette loos, suddenly makes sense)
- Use 230v tools anywhere on site? Every cord, tools, connection, distributor box etc needs tagged. It's for your Own Good, see. Expect $20 per item per year. Easily a grand a year if you are tool-addicted....
- Oh, and the local avaricious authority will want anywhere between $10 and $80K to hook you into services like power and the three waters.
Now, sing me a sad song about all a them Poor Folks without a roof over their heads.....but that list above sure answers most of Roelof's very good question.
Right to Build??? Ha.....