At first, Liu Bei was ill to help the Han Dynasty. At the end of the Eastern Han Dynasty, in fact, the whole society was in a mess, and with the Yellow Scarf Uprising Army, the life of the people was quite bitter. At this time, Liu Bei has set out to crusade against the Yellow Scarf Army. Of course, Cao Cao was still an official of the imperial court at this time, so there was no contradiction between Liu Bei and Cao Cao at this time, and the two sides did not form an opposition.
Cao Cao is getting bigger and bigger, and his ambition is getting bigger and bigger. At this time, Liu Bei gradually became the opposite of Cao Cao. In fact, as we all know, Cao Cao didn't have much ambition at first, but with the increasing power in his hand, his ambition naturally grew bigger and bigger, so Cao Cao was named Han Xiang, and he was actually a Han thief. At this time, Liu Bei's slogan was to crusade against cao thief and restore the Han Dynasty, which meant that Liu Bei and Cao Cao had always been antagonistic. For example, when Cao Cao was fighting in 10 week, Liu Bei went to support Xuzhou, although his troops were less. Of all the princes, only Liu Bei dared to do so. Therefore, it is obviously wrong to say that Liu Bei dare not compete with Cao Cao for the world.
There are many reasons why Liu Bei failed. First of all, although Liu Bei has got the whole Sichuan and Shu, Guan Yu has lost Jingzhou, and Han Shu Group can only generalize after losing Jingzhou. Although Zhuge Liang went to Qishan six times later, it was very difficult every time. In addition, although the whole Sichuan-Guizhou region has natural barriers, its population is relatively sparse, which limits Liu Bei's military strength.
The most crucial point is that Liu Bei launched the war of Yiling, which was a crushing defeat. This battle also completely destroyed the Han Shu Group. This battle not only lost the military strength of Han Shu Group, but also lost the reserve talents of Han Shu Group.