Blu is great...if you happen to live on an acre of land, and can sprawl out. Yes, they are friggin' expensive for what you get. They do try for the "factory-fabricated" efficiency you envision, and their big selling point (besides the cool factor of their designs), is the incredibly aggressive on-site build time.
And of course, everyone forgets that there *is* a market for extremely cheap prefab homes...till someone mentions the word "double-wide."
There's a reason Blu only supports a few plans, and limited customization. I'll tell you one thing that makes stick houses so mainstream, compared to prefabs like Blu is the ability to divide labor into distinct labor pools, and not have to act collectively like a borg to get a highly tailored job done. Instead, your teams can act more autonomously, independently, and adjust in the field and deviate from design, with the field installation SME orchestrating decisions as things go in. This is largely appealing because the whole collaboration is complex, imperfect and highly individual, with *many* wild cards (black swans..."unknown unknowns") that may change the course of the project. Designers are often completely ignorant of the wisdom of fabricators. And fabricators of one trade will sometimes be ignorant of the wisdom of other trades. And *everybody* is relatively ignorant of what mysteries hide underground before the backhoes actually break ground. With a house, these become an incredibly complex set of variables and dependencies. Alot of trades are working around each other, acting and adapting to the progress they see on site, and the sticks 'n bricks approach does allow for alot of onsite flexibility, with the architects/engineers as the "composers", the plans as the composition, and GC as the "conductor." With this division of labor, you get high flexibility, and high tailorability. You get cost efficacy, because you can bid out to a large pool of contractors that know how to do their individual trades.
It's certainly the *established* way to skin the cat.
You can attempt to "agilify" the whole process, which I think would be pretty cool. But think about how today's labor pools would have to collaborate to get that done, and you start to realize, you're asking for significant changes to an industry. You're literally asking for the Architect to become an expert conductor, "designing" at an pretty detailed level. Or...you're asking for the conductor to burn his/her time helping the Architect compose a better composition. All along, you're asking for the first position oboe player to chime in saying "if you force me to adjust my reed clearance, I won't have enough lung capacity to hit that 32-note spread your client so wants." And when they discover that hey...the core samples didn't reveal a rock ledge that will add $30,000 to the budget to dynamite and cart off, or you could just adapt to a foundation 2' higher...redesign...
I'm completely mixing my metaphor and my examples, lol. But you get the idea. I think of players like Blu like the small teams trying to disrupt the industry. But they really run some serious risks, and they can't bid out to a large pool of trades to do the work their way, because most of the players don't collaborate the way they would want to.
Building a shed, I had quite a few prefab options. I decided to roll my own, because I wasn't satisfied with the design and spec decisions made by the prefab manufacturers. Some had horrible specs (24" OC framing...notably 2nd rate materials). Some were great, but didn't fit my space criteria...or didn't fit under the County's height criteria. Tons of little nitpicks added up to push me to go custom. Now I'm doing a stick-built shed of my own design. And that's just a shed! It's super hard to get everything right in a prefab house operation.