His comments -- widely seen as out of touch and uncaring -- unleashed a torrent of bile in the press and on social media, with a petition on Change.Org calling for his ouster garnering 168,000 signatures by Friday.
"The cabinet should be led by a person who is competent, educated and cares about the country," wrote the petition's author, Alexander Li.
"We are seeing the opposite right now."
The lower house of parliament is obliged to debate any petition that gets 100,000 signatures.
"There's no need to compare," Medvedev said. "The issue is what you choose in life.
Teaching, he said, "is a vocation. If you want to earn money, there are a bunch of great places where you can do that quicker and better in business. And you didn't go into business.