There has already been a discussion on this topic, and the conclusion is more than clear. The point is that CM operates exclusively with BTC, and that it pays all participants in its signature campaign exclusively with BTC. Therefore, from their perspective, it is completely irrelevant what the price of BTC is compared to fiat - because 2 BTC per week today or 2 years ago makes no difference for them.

I may be wrong, but given the reputation CM has and the “pay as much as you want for service” policy, I have no doubt they are doing very well.