1. There‘s always a reason or two for the treatment. The problems with bite may affect your health in various ways. There’s aesthetic component in it, sometimes even cultural preferences for how your teeth should look like. But let’s say patient cannot afford to care about final position when signing up for the treatment. They just trust the doctor saying they need it. Failure mode: patient is unhappy with outcome and will ruin your business from marketing perspective.

2. Let‘s say the practice does it in old way, with impressions - no intraoral scanner. The scanner of impressions still needed, but it can be cheaper. Someone needs to build it and achieve required accuracy (let’s say, 50 μm). Who? Why? Failure mode: bad scan leads to aligners not fitting your teeth from day 1. Oops.

3. Let‘s say someone builds a good OSS alternative to OrthoCAD (Who? Why?), so that orthodontist on site could build a treatment plan and export it into series of 3D models for printers. Failure mode: good treatment plans are rarely possible or output is garbage (aligners do not fit, cause pain etc)

4. Maybe some company develops good plastic or patent expires, so that it is possible to produce it in India, China or other inexpensive location with strong industrial base. That would be cool, otherwise: non-compliant plastic breaks in patient’s mouth, decomposes with patient ingesting some toxic chemicals or is simply not strong enough to move teeth in desired position, so you have problem with 2nd aligner.

5. Maybe you get to this point, but you still need a printer that can maintain the same precision in printing. And you need a good cutting and finishing process. Someone needs to build such device. Failure modes are similar to the mentioned above.

6. The ortho supervision sounds easy, but how many patients in developing countries do even have a possibility to see orthodontist? They are definitely not in position to treat themselves.

So, in this process, what is good enough exactly? Who and why would drive the costs down while building an on-site solution?

These kinds of things can slowly move your bone structure over time. After all, that is their entire point. You don't want to accidentally mess up your teeth and jaw even more.

Smile Direct Club and co have shown its founded 100% in real risk of harm.

They were a company theoretically doing the same thing with still more resources than an average individual has, and ruined people's bites and teeth.

I don't think there's a good enough here

IIRC, yes. It’s been some time ago, I don’t know how manufacturing looks now. It’s different process compared to 3D printing at home. It doesn’t mean it should be different, it just has to maintain certain properties. I’m not chemical or bioengineer to go into detail of it :)