When Liu Bei was at his peak in Jingzhou, he should have been before he entered Shu. At this time, Liu Bei had mastered basically all the counties of Jingzhou. At this time, Sun Quan had just moved the seat of government to Moling and built the Shushu Dock. Cao Cao, on the other hand, moved the strategic center from Jingzhou to Jianghuai and attacked Wusuwu several times.
At this time, Liu Bei's strength increased greatly, and his overall strength may be weaker than Sun Quan's, but as far as military strength is concerned, it can be said that the two are on par. If Sun Quan took the initiative to attack Jingzhou, it would be difficult to get a bargain under Liu Bei's all-round counterattack. Instead, it created an opportunity for Cao Cao to send troops south.
For Liu Bei, although Cao Cao withdrew north, he still retained parts of Xiangyang and Jiangxia in Jingzhou. If Liu Bei was too confident, he took the initiative to attack Sun Quan. It may be possible to take Jiangxia into his pocket and drive Eastern Wu's army out of Jingzhou completely, but it will be difficult to go down the river.
And Cao Cao has always regarded Liu Bei as a great enemy, and when he has the opportunity, he will certainly not miss it. Moreover, before Liu Bei entered Shu, Cao Cao had just pacified Guanzhong, and Emperor Xian of Han allowed him to "pay homage to the nameless and go to the temple with his sword", which was the time when his momentum was the highest and the strongest after the Battle of Chibi. If Liu Bei dared to lead the main force to attack Sun Quan, Cao Cao would surely seize such an opportunity. As for whether to send troops to attack Sun Quan from the direction of Jianghuai or Liu Bei from the direction of Jingzhou, it is difficult to say.
That is to say, once Liu Bei and Sun Quan go to war, which side can win depends on Cao Cao's attitude. If he and Sun Quan cooperated, it was entirely possible to defeat Liu Bei. However, after the attack, sun quan could still hold Jingzhou. With Sun Quan's cleverness, he would not do such a stupid thing.
And if Liu Bei cooperated with Cao Cao, he could divide Eastern Wu. But with the grudge between Liu Bei and Cao Cao, how could he cooperate with Cao Cao? Moreover, he was also unable to digest the territory of Eastern Wu.
Therefore, Sun Quan and Liu Bei would not go to war at that time, because Cao Cao was there. If you have to choose a unique historical section, ignore cao Cao's existence and only look at the duel between the two. In the end, it is likely to be a lose-lose situation, and even if one side can win, it must be a crushing victory.