Anime why MMD than 3D anime is more smooth and exquisite, the national anime can not use the production of MMD method to produce 3D anime?

First of all, the reason for using 3D is that it is faster, less expensive, and requires less work. There is also no need for 2D animation that requires the production staff to have aesthetic and art related. The only thing you can do is to use 3D software.

Your MMD is fluid, but it's fixed.

Animation is a set of every single scene, an animation of at least 300 different shots more than 1,000 different shots, each of which must be produced separately. MMD is a set of dozens and still fixed.

The workload is there. Besides, animation production companies, it's all about money, not beauty. Including the Japanese animation company most of the route is to go to the volume, give how much money to do how much work, a lot of popular novels to change out of the low-quality is less money.