At that time
Shu was almost the same as Wu but territory was a abit smaller because they lost a large part of Jing Zhou to Wu
Wei still strongest, but the reason they didnt attack alot cos of few major reasons,
1. Cao Pi was the new emperor and Cao Pi wasnt a military person and didnt have ambition as much as his dad
2. The three kingdom keep changing alliance, when Wei attack Wu, Shu ally with Wu
when Wu attack Shu, Shu ally with Wei,
when SHu attack Wu, Wu ally with Wei
when Wei invade again, SHu and WU ally
there was no way out of this
First this is the ultimate plan n goal devised by zgl.
When most readers think lb need zgl.. But alternative view is thst zgl need lb more if he want to venture out to create his career.
His 三国鼎立plan is consider e best scenarios only to lb n fit to lb idea. First step to get that scenario, lb need to establish foothold.
That already dont fit into cc or sq coz they alresdy hav a foothold. E impact of his plan is not as big as other compare to lb thus zgl wont able to have great career responsibilty if he join sq. Plus sq already hav a big group of advisers thus his plan will definitely greet with disagreement among other more senior advisers.
Under lb clan where everyone know only how to fight but no concrete or ultimate goal, zgl plan is just like a god send.
Second, lb not onlu wan restore han but also peace for his ppl. Again zgl 三国plan fit in. With e 3 parties in balance, sensible ruler wont declare war without strong reason. = ppl in peace. If u know or read history expert writing abt zhl, e word sensible is e crucial. I explained later.
Third n last, wait for e moment of change. Established 3 parties then it is e matter of waiting games.. Observe astrology etc to predict change which advantage to lb n then declare campaign toward northen.
Once e northern is conquered, east wu will submit. Zgl also stated this in novel, if no major change to lb adv, at least he got a stronghold to stand n continue to serve ham im his own way. This is a final win win situation compared to lb current state during their meeting at zgl's kampong.
But when all established, lb lost his sensible after his close bro guan yu was captured n exe by wu. Zgl strongly advised not to go war as e 鼎立 situation is still not matured. There is no major change based om e astrology n lb is attacking e wrong target. Zgl dont even want to go to e campaign w lb n assign 马梁 to go om his behalf. Noval or articles domt state but noval experts guess zgl already predicted lb campign will lose. Thus e. Fictional 八卦trap 陆逊 story is born to make noval more exciting.
Overall it just show how impt is this gridlock to hav peace during tat time.
Thus it is no surprise when 1 party attack, the other 2 form allies.. It is effect of the ultimate plan, 三国鼎立.
It is meant to have "no way out" but it create peace. Maybe e "wait for change" quoted by zgl to lb is a carrot to create such gridlock.