So powerfully, we don't really disagree- I concur that my use case (replacement parts for toy robots) doesn't justify even a 500$ 3D printer- but the communal one we share at university was extremely valuable (did I mention the quotes from services like Shapeways for the part were in the 17-25 dollar range, where I was charged 3-4 bucks?). Moreso, the REAL value here is in all the crazy designs I've been concocting since then, like the adjustable desk I've been toying with building for ages, but always found my toolbox, workspace, and expertise somewhat short to make the gear setup- the portion of the project that intimidated me would be trivial and cheap with this 3D printer- and this printer, it's one of the ones that really sucks! This breaks that barrier right down, and that's all technology is really for, anyway- to help us make our visions into realities.
You obviously know more about materials than I do, but I think that your perspective is skewed by upper limits- you're trying to decide this technology by comparing it to other tech that it has zero need and zero business trying to compete with- when we DIY guys require materials that strong, then maybe we can talk (not saying it wouldn't be nice, and break down more barriers, I'm saying that it sounds like you're saying that unless it can compete with injection molded ABS plastic, it's not worthwhile, and I hotly contested that assertion), until then, you're trying to shortchange our moon rockets because they won't get us to Mars, and that's pretty silly, in my book, even if it's true.
So, indeed, hobbyists machine- someone purchasing this as an appliance like a refrigerator- meant for convenience and time-savings, I can agree that they'll be disappointed. In the meantime, hobbyists who only want to give the vision-to-reality ratio a boost are going to continue to be tickled pink at their 3D printers, and I suspect that their enthusiasm will drive enough interest and investment in the technology to maybe deliver some of those high-quality, cheap Laser sinterers you mentioned before- all possible as long as there's an enthusiast market to consume the hobbyist level iterations along the way! :D
Your story is very positive, but it falls a long way short of justifying the purchase of an expensive machine and the investment of many days of effort in learning how to use it. How many people have a burning need to produce hundreds of dollars worth of spare parts for toys?
>the materials science is an obstacle made of tissue paper- as in, we're already blowing through it handily. I don't know what you're printing with
I've seen test results from the absolute best case scenario - professionally designed parts printed on a $200k Stratasys machine using ULTEM 1010. The material properties just about match injection molded ABS. Parts made on consumer machines using ABS or PLA filament are generally an order of magnitude worse.