Do you think that if you were not a Christian, this is something you would still believe in?
Probably no or yes. I don't know. Who knows what I would come to believe? What if I would think myself as better or smarter than other people, how I would come than to accept the truth of humility? Probably I would deeply despise such a teaching, thinking its for 'wussies' and for 'losers'.
Can one go to Julius Caesar, or to Napoleon, and say to both of them : 'Do you know you are small? Do you know you live in a illusion thinking that you're any better than other people? Humble yourselfs, big boys. Come to face the reality!'
Or can one go to a big rich man, which has many many casinos, social power, incredible and outstanding capacity for making money out of nothing, or whatever, everything which is considered to be great, and say to him: "Hey man, you are just like the other people. You are mortable, you will die, and you will die as you were born, whithout nothing to take with you. You are just like the other people! Get off from your castle of illusion !"
Can the people that are 'great' believe the truth? They live in a illusion, and its hard for them to be faced with the truth. They despise the word humility.
The Bible say God has some ways to make the kings bow down before Him. Here is Micah 7:2
2 The good man is perished out of the earth: and there is none upright among men: they all lie in wait for blood; they hunt every man his brother with a net.
3 That they may do evil with both hands earnestly, the prince asketh, and the judge asketh for a reward; and the great man, he uttereth his mischievous desire: so they wrap it up.
4 The best of them is as a brier: the most upright is sharper than a thorn hedge: the day of thy watchmen and thy visitation cometh;
now shall be their perplexity.