It hardly seems democratic; just because you come from a family of Kohanim or Leviim, why should that qualify you for extra honor? We should make them take their turn in the back of the queue like the rest of us plebs. What have they personally ever done to deserve their seat at the front of the bus?
In Temple days, the priestly caste was singled out from their brethren to serve Hashem and bring blessing to the nation. The Leviim would sing during the service and the Kohanim would offer sacrifices.
Nowadays, they do less and get less in return. The relatively small measure of honor paid to them is more of a historical reference to their ancestral heritage than a reflection of their personal celebrity.
However, those public marks of respect aren’t really what being a Levi or Kohen is all about. Success in life is about giving, not receiving. The true measure of distinction of the priestly families was in their role of following in Hashem’s ways and teaching Judaism to others.
But you don’t need to be born to a family of priests to live like one.
The Rambam teaches: “Not only the tribe of Levi, but any one of the inhabitants of the world whose spirit motivates him, and he understands with his wisdom to set himself aside and stand before G-d to serve Him and minister to Him and to know G-d. he is sanctified as holy of holies.”