Why did Qin Shihuang emigrate after destroying the Six Kingdoms?

Emotionally, Shang Yang and Lv Buwei both came from Wei State, which contributed to the rise of Qin State. It is normal for Qin Shihuang not to attack Wei State.

From a realistic point of view, Wei's strength is not strong, and it has surrendered, posing no threat to Qin. In the face of the de facto vassal state, even if Qin did not send troops, Wei had already existed in name only. Why did Qin Shihuang start a new stove (of course, Wei was still dying in the period, which is another story)?

Although Wei Guo was neither a finalist of "Five Overlords in the Spring and Autumn Period" nor a finalist of "Seven Heroes in the Warring States Period", he was also a veteran of the vassal states, spanning two stages: the Western Zhou Dynasty and the Eastern Zhou Dynasty. 1907, he passed on 4 1 monarch.

In the early years of the Western Zhou Dynasty, Kang Shu, son of Zhou Wenwang Jichang and brother of Zhou Wuwang Ji Fa, enfeoffed Wei, and successively established Chao Ge, Chuqiu, Diqiu and Wang Ye. When he moved eastward, Guo Wei made great efforts to govern, and Guo Wei became a big country once.

However, the good times did not last long. In the following hundreds of years, the country was destroyed several times and the country was successfully restored several times. As far as strength is concerned, it is long gone. During the Warring States Period, Wei occupied Wei, making the monarch of Wei the "monarch" of Wei. Although the signboard of "Wei" is still there, it has actually lost its national sovereignty and is no longer a "country". It can be regarded as an institution under Wei.

Note: Feng Jun was the owner of fiefs during the Warring States Period. He is no longer a vassal, so his territory cannot be called a country.

Since then, the leader of the country is no longer "Gong Wei", but "Wei Jun". At the end of the Warring States Period, in 24 1 year BC, the State of Qin attacked the State of Wei, and divided the original Puyang area of Wei into the East County. Wei Jun crossed his toes and moved to the wild king (now Qinyang, Henan). Wei became a vassal of Qin again-Wei Jun was abolished by Qin Ershi only in 209 BC.

But before that, Wei was no longer an independent "country". As a result of the Qin-Wei War, Wei changed from a "colony" of Wei to a "colony" of Qin. Of course, there is no need for Qin Shihuang to deliberately "destroy" Wei, which is no longer a "country". What do you think of this?