After Liu Bei's defeat, it was not that he did not dare to return to Chengdu, and as the Emperor of Shu Han, he was not faceless to face his courtiers, in fact, he stayed in the White Emperor City because he had his own plans and purposes. Liu Bei progressed smoothly in the early stages of the Battle of Wu, but by June 222 AD, the pieces of armor that had been burned by Lu Xun's fire were not left, and countless personnel, armor, and materials were lost. Under these circumstances, Lu Xun naturally had to pursue liu bei with all his might, and had a great plan to kill Liu Bei. After the defeat, Liu Bei retreated from Yiting to Zigui, then to Yong'an, and finally remained in the White Emperor's City in August of the same year. At this time, the Wu generals Li Yi and Liu Aqian pursued them reluctantly, and kept following Liu Bei's escape. Therefore, at this time, the White Emperor City had actually become the forefront of the Shu Han against Eastern Wu.
Liu Bei's purpose in garrisoning the White Emperor's City was to use himself as bait to induce Eastern Wu to fight. So, where is Liu Bei's confidence? Confidence 1: The white emperor city is dangerous, easy to defend and difficult to attack, so it was once described by Gongsun, the king of Shu during the Wang Mang period, as the place where the capital was built, and the emperor was called "White Emperor", so there was a White Emperor City. Its land is located on the north bank of the Yangtze River at the mouth of the Qutang Gorge, east of the Chumen Gate, west of the Eight Arrays, back to the High Gorge, in front of the Yangtze River, surrounded by water on three sides, majestic land and water, magnificent, has always been a place of contention for soldiers Confidence Ii: If the main force of Eastern Wu is attracted to the area around the White Emperor City, in the face of such a good opportunity, he does not believe that Cao Wei will be indifferent. Because the White Emperor City (present-day Fengjie, Chongqing) was at least 800 miles away from Jingzhou (the current highway distance is 362.4 kilometers), it would be difficult for the army to quickly return to help.
This was the real reason why Liu Bei retreated to the White Emperor City. In the second year of the defeat of the Yiling Army, Liu Bei died, and several rebellions quickly occurred within the Shu state, zhuge Liang had to reconcile with Eastern Wu again, and it took nearly 5 years to quell the turmoil in the Shu state. Therefore, Liu Bei was guarding the White Emperor City, and the defense of Eastern Wu was secondary, and the prevention of civil unrest was the main one.
You said that Liu Bei could not go back, he had his own task there. At the same time, it can't go back to it. The physical illness was so severe that there was no reason to go back. Cao Pi did not want to attack the Shu state, but directly wanted to attack Eastern Wu, and in addition, Liu Bei did not have the face to go back.