But legal services in general are an expensive, labor-intensive craft industry. Just like any craft industry, there's probably scope for low-touch industrialization alongside high-end bespoke craftmanship. Clothing is a good example of what I'm talking about--rich people have tailors, everyone else buys off the rack. What you have now in law and may other professions only works for the high-touch case.
Atrium (google them) is trying to get around this by having a traditional high-touch law firm use a lot of software provided by a standard silicon valley-financed venture capital startup. They're basically laundering legal fees to the startup side via the law firm. I'm not sure of the exact legalities but we need more stuff like this.
Access matters. A system that, for completely well-intentioned reasons, attempts to guarantee that everyone only gets the best, means the low end will never have access at affordable rates. It's simple economics. Until practitioners work for free (they won't), or there's some way to do things more cheaply, the bottom won't get served.
For the same reason or not-reason you can have any other company owned by people who are not experts in the company’s subject. This is probably good for lawyers but otherwise this restriction makes no sense.
This is very different from the chip engineer scenario. It is the most important reason why non-lawyers are not allowed to own law firms. Because non-lawyers are not bound by rules that require them to put profit motives second in many circumstances.