Kostner's results in those two seasons:
2012-13
1st, Golden Spin
1st, Europeans ($20,000)
1st, Challenge Cup
2nd, Worlds ($27,000)
2013-14
3rd, Cup of China ($9,000)
2nd, Cup of Russia ($13,000)
3rd, Europeans ($8,000)
3rd, Winter Olympics (4th in the team event)
3rd, Worlds ($18,000)
Golden Spin and the Challenge Cup would likely have had no prize money. I don't know what Italian Olympians received for medalling in Sochi. My guess is that much of her income in that period came from shows and sponsorships and a lot of it was used to fund her training. She is not the equivalent of a footballer or baseball player, who can pay a hefty fine without getting into financial difficulty.
And I see no reason why Kostner should be fined to that extent. It suggests that a two year ban effective immediately would have been a reasonable punishment, which I disagree with. I doubt such an option is on the table, though, so it doesn't matter.