I agree with all the posts referring to the cost of rubies, they are pretty ridiculous. Sadly, that's just the way it is. Obviously thousands of people are happy to throw down $50/$100 a week on this game, something that the average worker and player of the game could not or simply would not.
Kabam is essentially a gambling site, think of them as a Vegas Casino. They have gambling psychology wired, every chest you can buy is a gamble, the whole game is based around that and the house always wins.
They are a large corporation with a huge turnover, everything is monitored with flow charts monitoring spending everyday. If for one second they thought that by lowering their prices they would create bigger profit margins, they would.
On the plus side, were the ruby players not to buy rubies, we wouldn't have this game...and it's a fun game. I'm not a ruby player, however, I have bought rubies in the past, very infrequently, never more than $10.