The kind of industry that is willing to focus on R&D for decades, with extremely low short-term returns and full of risks is basically good for both Japanese and Germans. They are engaged in a certain industry not so much for profit as for tradition. For example, they can focus on nailing for generations, only nailing, even if they can't save any money, they must be the first in the world.
In fact, there were many such people and families in China in the past, but they died out in a series of turmoil in recent years. In impetuous China society, such people are hard to understand. At present, people in China are not interested in things that can't be turned into money immediately.
So twenty or thirty years ago, there were factories in China, such as Seagull, Hongqi and Phoenix, which could make SLR lenses (although the quality was average). Now, even if these factories have not closed down, they can only make adapter rings and lens covers.
The unreasonable state system, the unsupported policies and the incomprehension of the society have created a bad market environment, and the nascent optical industry in China has to be strangled.
Therefore, most of the SLR lenses currently on the market come from Japan and Germany. Compared with these two countries, Germans pay more attention to the technology itself and have not grasped the market well. The Japanese are more sleek and do business better, so the Japanese are the first in the camera market.
Supplement:
Why do you say that the lens industry needs tradition and accumulation ... We should know that each lens is a separate patent with high technical content and needs a lot of R&D investment. R&D does not mean income. Probably nothing will be developed. If you were me, would you make such an investment?
Not only does it need research and development expenses, but also the lens itself is a high-cost industry, optical glass itself is very expensive, and the grinding equipment is not Chinese cabbage, so the production risk is great. So you see that there are tens of thousands of lenses, which are actually not worth that much in terms of cost. Only considering the loss in the production process will it be so expensive. For example, the loss rate of producing an aspherical lens is 100%, which means that half of the lenses are scrapped in the production process, and the cost of scrapping is also included in the final price. In this way, the price of the lens is very high. If the lens manufactured can't reach the quality required by the market, the manufacturer will lose money.
Those lens manufacturers in Japan are also operating on a shoestring, taking many detours and being eliminated by the market. Only those who survive have the present scale. If you look at the current lens manufacturers, you think they are all profiteering, which has been accumulated for decades. Now there has been a monopoly in the lens industry. Now a new enterprise intends to enter the lens manufacturing industry, and I'm afraid it will lose money in the first ten years.