Russia and China do not publicize their military technology for a number of reasons.

• Security: Publicizing military technology can give potential adversaries an advantage. This is because it can reveal the capabilities of a country's military, as well as its weaknesses. This information can then be used to develop countermeasures or to target specific vulnerabilities.
• Economic: Military technology is often a source of national pride. Publicizing it can help to boost a country's image and to attract foreign investment. However, it can also lead to the loss of valuable intellectual property.
• Strategic: Publicizing military technology can reveal a country's strategic intentions. This can be counterproductive if a country is trying to maintain a degree of ambiguity about its military capabilities.

In addition to these general reasons, there are also some specific reasons why Russia and China may be reluctant to publicize their military technology.

• Russia: Russia has a long history of secrecy surrounding its military. This is partly due to the country's history of conflict, and partly due to the fact that Russia has a large military-industrial complex. The secrecy surrounding Russia's military technology makes it difficult for outsiders to assess its capabilities.
• China: China is also a secretive country when it comes to its military technology. This is partly due to the fact that China is still a developing country, and it wants to protect its technological edge. It is also partly due to the fact that China is a major arms exporter, and it does not want to give away its secrets to potential buyers.

The secrecy surrounding Russia and China's military technology makes it difficult to assess their true capabilities. However, it is clear that both countries are investing heavily in their militaries, and they are developing some very advanced technologies. This is a cause for concern for some countries, as it raises the possibility of a new arms race.

It is also worth noting that the secrecy surrounding Russia and China's military technology can make it difficult to cooperate on issues of mutual interest, such as arms control. This is because it is difficult to build trust when there is so much secrecy.

Overall, there are a number of reasons why Russia and China do not publicize their military technology. These reasons are complex and multifaceted, and they reflect the strategic interests of both countries.