Lee's right tho.
The WG allows the Yonko to exist for balance purposes. The Yonko keep each other at bay which means that no one will eventually pose a serious threat to the WG in the form of finding the One Piece.
The Navy might be able to take them on.
But for which purpose?
Seizing Wano in case Kaido goes down must be a direct order from Imu. Neither Lucci nor anyone else in the government is sure it will even come to this.
So, defeating the Yonko, namely Kaido in this case, only for the sake of conquering Wano, would never be the WG's objective. But in case Kaido goes down anyway they want to seize the oportunity.
As you said, the Marines are merely the outward face of the government. They don't make the decisions. The Gorosei and eventually Imu make them.
@Fleet Admiral Lee Hung
For one, if Government wanted 4 Yonko to exist, they wouldn't attack Whitebeard 2 years ago and they wouldn't get WB killed by plotting with many different sneaky plans during the war. They would just execute Ace in a different location, and they would avoid fighting with Whitebeard. It would be easy.
For 1 year there was only 3 Yonko until Blackbeard become a Yonko 1 year before, so what happened to balance during that 1 year? Nothing.
If there will be 2 Yonko or 1 Yonko left, it won't happen anything to balance as well. ''Balance'' only existed with the help of Shichibukai, it means that government is desperate to fight Yonko, since they need ''balance'' they take help from other pirates to make things balanced against the pirates, since its 1 Yonko > Larines, only when Larines gets help, it's 1 Yonko = Larines + Shichibukai, once Shichibukai was removed balance is also removed, then it means they trust their own power and Vegapunks to fight Yonko with 1 Yonko = Larines + Vegapunk's SSG, their objective was always fighting Yonko,
which is why Shichibukai existed, and which is why Kaido said Government STILL plans to attack Yonko even after removing Shichibukai.
The ''US'' here is Yonko, the Government and Larines always planned to defeat Yonko.
Shanks become a Yonko 6 years ago, it was 4 years ago when it was pre-TS, before Shanks, there was also 3 Yonko.
That 4 Yonko balance thing is very easy to debunk, as I just did.
It's always for 1 Yonko > Larines, only when they had Shichibukai, they are in balance and it becomes 1 Yonko = Larines + Shichibukai.
Shichibukai also existed so
they could fight against Yonko, you think they would allow some pirates to be
legalized if they can alone stop Yonko? Shichibukai only existed because Government needed other pirates to FIGHT Yonko, they don't want Yonko to exist nor legalize pirates like Shichibukai, but
they had no other choice.
They only want to seize Wano if Kaido loses, because CP0 just admitted in this chapter TWICE, that
they think Kaido is invincible, and they can't imagine Kaido is losing, same reason why they don't seize Wano for themselves. Because of the idea that Kaido not losing to anyone.
CP0 (who works directly under Celestials and Imu) literally
begging for weapons from Wano Shogun, because they needed weapons to
fight other pirates. You think they would put themselves into this situation willingly and be
desperate when they could defeat Kaido and seize the weapons in Wano?
''After all you were desperate enough to go to a pirate to buy the weapons you needed to fight Pirates.''
You think they would let Kaido exist and then still
beg for the weapons to
fight other pirates?
Lmao, get out of here.
As for troll Lee ;
This guy is always going to lose.
Worstgen working hard for protecting Lee the Admiral wanker, who spread fake spoilers and insult people.
Sanji! 
