First of all, that looks like an absurdly good value for only ten bucks. I think the price makes it seem like less of a plan than it probably is.
But, I think that people who have enough skills and resources to build a frame like that are likely to want something that's less like a commodity item.
If it were simpler to build, it would appeal to more people who want something cheap and expedient. If it were a more versatile and configurable design, it would appeal to more of the folks who already have the skills and tools to make it. The way it is, it seems like an alternative to many complete bikes and frame kits that can already be bought for not too much money.
