Celtic Heroes

Sorry for the noob question but I must ask. To my understanding of the platinum/gold ratio it's 1 Platinum = 100 gold, so thus resurrection idols cost 100 gold each. Using that same logic a 40 platinum super combination elixir should cost 4k. However, everyone sells those for 10k. Am I missing something? Mathematically this doesn't make any sense.

It was never 1:100. Long time ago it was 1:200 or 1:250, now the price of plat items just depend on server supply vs demand.

Idols are dirt cheap because there's thousands upon thousands of them floating around. It's just simple economics.