There was no reason because Garp already proved superiority over them. It's their turn to challenge Garp.
Also, you as well dodged my question.
Garp is a Marine that falls under the WG's authority. The Government values the existence of the Yonkou system to prevent the rise of the new PK. No Marine up to this point ever supported the governments beliefs, but they fall under their rule, that's why Garp never went after them.
Marineford proves my point. The Government never went after any Yonkou, but they waged war against WB and risked to destroy the balance without a second thought if it was for the death of Ace, the man, with the potential of becoming PK.
Have your answer ?
Now answer mine pls
garp prove superiority to bm and kaido but it bcause they are different. mihawk beats zoro 2 years ago with pendant. aokiji beats monster trio with neg diff 2 years ago. luffy suffers total defeats against akainu and all of three admirals 2 years ago. zoro lost to kuina 2000 times.
doesn't meant 40 years later thing will goes same if same matchup happens. ppl changed. some they pass their prime. some enter their prime. some get way stronger and some get way weaker.
why garp didn't goes to war with kaido or bm later after God valley because he knew it was a suicide mission he make it just personal. wg need to assemble at least equal to marine ford arc if garp want to face kaido or bm.
god valley isn't just about him vs rocks. it was also about Roger and his companion and marines. and kaido was just a teenager that prolly as young as pre ts luffy.
even roger avoid direct confrontation against big mom.
garp already proved his superiority yes 38 years ago for certain day.
but big mom and kaido had already prove their superiority not just to garp but against WG and marines for over 20 years.
they are been reign on new world over 20 years without getting touched running their dirty businness.what Sengoku do? what garp do? nothing. they just watch.
wg support them from the back and front. their reason is to maintain the balance.that is total bs. what happen back on roger era? even top dogs like roger or whitebeard get chased by fodders marine.they get hunt countless time. WG don't even care about balance because they were think they are superior than pirates. but right know things changed. all because those four emperors.
back then they are sending admirals like garp Sengoku to response the meeting of shiki and roger at edd war. but right know even garp and kizaru think twice to hunt down rayleigh at same time to whitebeard. or like akainu think twice to deal with bm kaido possibly alliance.they don't just go casually fight and war the top dogs crew like the past.