Why does it make all these comparisons?
Radak: The verse equates each pair - this is like "Kamocha Chemohem" (Shoftim 8:18), "Kamocha k'Pharaoh" (Bereishis 44:18). When they destroy the land, the destroyers will not recognize the honored or favor the great. Everyone will be equal in the decree.
Malbim: When they go to exile, all will be equally lowly and disgraced.
Why does it say "cha'Am ka'Kohen"?
Radak: Kohen is a master over the nation, like "Yisro Chohen Midyan" (Shemos 18:1).
Why does it say "ka'Eved kA'donav..."?
Rashi: This is unlike travelers, that the master leads his slave, and the mistress leads her Shifchah - the master and mistress are honored, and the male and female slaves are lowly. Rather, when the captor leads his captives, all are equal in front of him.
Radak: Even though a slave is the monetary acquisition of his master, also his master will be a slave, like him.
Why does it add "ka'Shifchah ka'Gevirtah"?
Malbim: A Shifchah is more submissive to her mistress than a slave is to his master - "ch'Einei Avadim El Yad Adoneihem k'Einei Shifchah El Yad Gevirtah" (Tehilim 123:2).
Why does it say "ka'Koneh ka'Mocher"?
Rashi: When the nation dwells securely in its inheritance, a buyer is happy and a seller is sad, for his sale will not return to him. When captors lead them [to exile], a buyer is not happy and a seller does not mourn. Similarly, a lender is like the borrower. The borrower does not have what to pay, and the lender, even had he not lent, the captor would have taken [his money].
Radak: The buyer is greater - he is wealthy, and one who sells his inheritance needed to sell due to his poverty. The former is like a master 1 over the latter - "Ashir b'Rashim Yimshol" (Mishlei 22:7).
Malbim: Not only will mastery and authority cease. Also monetary obligations and the attribute of being rich will cease. The buyer will lack inheritance (land) just like the seller.
Why does it say "ka'Malveh ka'Loveh"?
Radak: Normally, the lender is like a master - "v'Eved Loveh l'Ish Malveh" (Mishlei 22:7).
Malbim: Not only will there be no difference between buyers and sellers of land, for one cannot take land to Galus. Also the lender will be like the borrower, for also money will not remain.
Why does it say both "ka'Malveh ka'Loveh" and "ka'Nosheh Ka'asher Nosheh Vo"?
Rashi: Loveh applies to money, and Nosheh applies to all other things [owed], such as wine, oil, grain and honey - "Ki Sasheh v'Re'acha Mas'as Me'umah" (Devarim 24:10).
Radak: Loveh applies to money, and Nosheh applies to food.
Malbim: Nosheh Vo refers to one who cannot pay, and his creditor demands payment. He is worse than a regular borrower. Even so, all will be equal, for they will lose all their property.