Pan Masala bhai, the hadith you use all the time to prove something has no caste angle . It was a prophecy. Moreover, there's a reason why only Quraish had to be leaders and not other tribes.

Please read this thread to know why Quraish had to be chosen as rulers [1/10]: https://twitter.com/AnisShafiullah/status/1305880512284651521

Quraish were unwritten rulers of Arabia who commanded immense respect & influence even before Islam arrived in Arab. Prophet SAWS comes from the same tribe. Socio-political structure of Arab that time was such that Arabs would hve never accepted a Prophet from a weak tribe [2/10]

When other Quraish leaders expelled Prophet SAWS from Mecca, most tribes rejected Him and His Message. It was because Quraish commanded such influence among all tribes of Arab. When Prophet SAWS migrated to Yathrib (Now Holy City, Madeena) , other tribes embraced Him [3/10]

But still His influence and acceptance was confined only to a region and only after conquest of Mecca and the polytheist Quraish later embracing Islam en masse, and Prophet Muhammed SAWS becoming their leader, the rest of the tribes of Arab started recognizing Him & Islam [4/10]

This is how Prophet SAWS united whole Arab as equals under fold of Islam using His Quraish privilege to unite all other tribes and spread religion of Allah. But after His demise, this unity was under severe threat, mainly because the next leader (Caliph) had to be chosen. [5/10]

Now while choosing a leader, each tribe would have endorsed someone from their own tribe. With a tribe from Madina already in plans to declare their Caliph, this could have led to a Civil War as other tribes would not have recognized their leader, especially Quraish [6/10]

Prophet SAWS had worked hard to unite rival tribes, who killed each other since centuries, as equals under Islam. Quraish (with their reputation & history) on other hands were seen as fitting rulers & a leader from any other Arab tribe meant collapse of unity & utter chaos [7/10]

Prophet Muhammed SAWS understood this dynamics of Arab rule, most Quraish were recent converts and conquest of Mecca meant conquest of entire Arab. Hence, due to dynamics & political structure that time, only Quraish leader could have ruled the Arab to avoid civil war [8/10]

Quraish was a tribe, a powerful and dominant one, who commanded respect and authority even before Islam. It has nothing to do with caste system. It actually proves how effective was Prophet's SAWS reasoning and insight into dynamics of Arab Socio-political structure [9/10]

In conclusion, when He SAWS said the political leadership will remain with Quraish as long as they follow Islam, he meant it by acknowledging their leadership credentials & influence. It was practical, most viable solution. That's what happened. There's no caste angle [10/10]