The fact that "certification" (in the conventional sense) of aircraft is expensive is besides the point. Certification implies standards and safety and I'm trying to make the case that our amateur built planes retain some of that...
Homebuilts aren't "certified" to any standard. AC 43.13 only defines "Acceptable Methods, Techniques, and Practices" (it's right there in the title). There's nothing that requires a homebuilt to even meet that--it's a good idea, certainly, and I would think that most DARs and A&Ps won't sign off a homebuilt that doesn't meet it without a good alternative method--but you could easily make an airplane that meets every aspect of 43.13 and yet is a deathtrap--barely stable, unable to take flight loads without breaking a spar, prone to fatigue cracks after 100 hours, and an engine fire waiting to happen (and unable to withstand the heat when it does).
Certification (e.g. to Part 23/25 standards) is a whole lot more beyond the basics of standard good practices and workmanship. And it goes beyond designing something. It involves extensive evaluation of every aspect of the design from an engineering and construction aspect, a lot of testing at the sample, component, system, and aircraft level, and approval by FAA representatives that the specific design complies with those requirements.
Approval of a homebuilt certifies nothing--plenty of aircraft have been approved by a DAR and issued an airworthiness certificate (coughRaptorcough) despite glaring design deficiencies. I wouldn't try to represent to anyone that a homebuilt has been somehow "certified" to a safety standard.
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From another perspective, I did my initial training in a rented certified aircraft (C150), like most pilots who start their flying in the civilian world. As it was rented, I never really got involved in anything beyond filling it with gas.
However, at that point we were most of the way through building my dad's RV-6; he flew shortly after I took my checkride. So from an ownership and maintenance perspective my first exposure was homebuilts, and it nothing seemed unusual about that--after all, I grew up helping Dad fix the cars, work on projects around the house, fixing my bike, building my computer, and so on. DIY was just the natural order of things, and there wasn't even a question when it came time to my own airplane--I was going to build it.
I never truly realized how strict the certified world was until I moved from the R&D labs at work, to the in-service support side. Granted, I'm in the world of Part 25 jets, repair stations, and the like, but it was mind-blowing how restrictive that was--especially once I realized that most of it was the same even for light aircraft. I understand where it comes from when you're talking about aircraft carrying the general public, but it sure seems like a lot of overkill when it comes to privately-owned personal aircraft. For sure, it's not a headache I want to deal with; quite honestly, you couldn't
give me a certified airplane.
Unfortunately the FAA seems to operate under a one-size-fits-all standard; they crammed everything into one category years ago and even though the entire world has changed around them, they don't seem to want to acknowledge that.