It's not that the technology doesn't exist yet, it does.
Is the bottleneck at the factories? Too expensive to incorporate/replace existing mass production equipment?
Whoever jumps first, is going to have a huge 1st mover advantage.
Production is also a problem. Small Batch production is typically 5-10x more expensive than the long lead time Large Batch production. Individual production can be up to 100x more expensive. The cut isn't the problem; a master tailor might allocate 5-10% of the 10-30 hours of making a bespoke suit to matters of cut. Cut is also one of the few areas where small batch manufacturers have cost parity with large batch manufacturers. Assembly is what makes custom production so difficult. Even with super-precision robotics, dexterity is a huge problem. Most large batch manufacturers only automate 5-10% of the total stitches for a garment...the rest is done by high-dexterity human hands.
Its a hard problem. A more solvable problem would be to drastically expand the number of possible size options, and use state of the art supply chain techniques to bring them to cost parity with larger companies and their smaller size selections. I'd be interested in doing quite that if I found the right co-founder...but that itself is a problem of its own :)
If you are overweight it could show ads of gyms/treatments/diet-food; not that there is anything wrong with that, BUT think about the new industry that opens up for penis enlargenment spammers.
Living the joke behind, I think is worth to think about the implications if/when something like this gets implemented.
I have a feeling that the data would be more likely to be peddled to McDonald's than 24 Hour Fitness.
When you have enough money to pay them more than the brands and retailers who are buying their ad services.
Example: I don't want Glass or personalized search, nor do I want body scanners, and I am completely fine without custom-clothes tech. My preferences shouldn't apply to all HNers.
If anything being sponsored by its industry, like a technology standards authority, should make it less likely to make exclusive agreements.
However, some of the examples I've seen of the clothes include issues that a tailor would have fixed, like a roll between your neck and shoulders. Maybe it works like a Flowbee does for haircuts, and it just applies a consistent offset from your body, rather than understanding which areas should be close fitting or loose. That the descriptions talk about precision to fractions of a millimeter makes it sound naive about what matters to a skilled tailor.
However, it doesn't sound like there is anything preventing multiple users from using the same measurements, whether they make suits, jeans, undergarments, or wetsuits.
For example, a cnc fabric cutter could cut all the panels out of stock kept on site, and a person could then sew the panels together into an actual outfit. Would require quite a bit of initial outlay for the materials (less if the pattern on the material is printed on-site), and the hourly wages of a sewer on site, but I think it would certainly be doable.