1: According to historical records, there are other reasons for the lack of personnel in the Third Red Front Army.

The development of the Chinese Workers' and Peasants' Red Army from army to front army has gone through a tortuous process. Before January 1930, the central government had no unified plan to organize the Red Army. At that time, the Central Committee believed: "Currently in China, only the troops of Zhu Mao and Peng Dehuai can be called the Red Army, and the rest such as He Long cannot be called the Red Army" and can only be counted as guerrillas ("Politics of the Second Plenary Session of the Sixth Central Committee of the Communist Party of China") Problem Report Record, June 25, 1929). Therefore, the organization and designation of the Red Army in various places also went their own way.

2: The more specific reasons are:

The Red Fourth Front Army that entered Sichuan in the autumn of 1932 also developed into five armies with 80,000 soldiers. As the main force of the Red Army, in addition to these two units, there are also the Second and Sixth Red Army Corps. In July 1936, the Second and Sixth Red Army Corps were combined into the Second Red Front Army in accordance with the instructions of the Central Committee, while the Third Front Army had to be short of personnel. In October, the First, Second, and Fourth Red Front Army joined forces in northern Shaanxi. In August 1937, these three main Red Army units were ordered to be reorganized into the Eighth Route Army of the National Revolutionary Army. There was no need for the Third Red Front Army to be reorganized.

So this is the reason why the Third Red Front Army is short of personnel! Please refer to it.