Well, having known him for a year or two on ebikesforum, I can tell you he started by building eBikes out of muggle bikes. Learned a lot and is keen to help others.

I suspect he found the basic bike worth the money, but not paying hundreds of dollars for Specialized-branded trash cans. Kind of like declining the expensive factory "cargo organizer" option on your car, in favor of something aftermarket for a fraction of the price. If one doesn't find value in the branding or construction, one sometimes goes the DIY route.

Poke around on his site, he's quite the eBike handyman and shares his knowledge even when it means a ton of extra typing.