I'm no expert on how the math adds up, but a Crunchy subscription is only $7 a month, Funi $6, and most people watch dozens of shows under those subscriptions. Being a big fan of this series, I probably only contributed pennies to the actual creators once it's all divided up. I'm sure those pennies add up when viewed in mass, but compared to manga sales, where one could potentially spend over $100, or blu-ray sales which could also be $50 or so, overseas fans could have contributed much more. But Since the manga will likely never receive an official English release and Funimation blu-rays won't be available for some time, there's really nothing we can do as fans to show support, besides maybe buying imported merchandise, but good luck with that ordeal. It's just frustrating to see something tank due to low sales, when you yourself have no opportunity to chip in.
Like you said, it adds up. Most NA anime releases sell a couple thousand units if they're lucky, and a large percentage of that goes to retailers and distributors. CR recently reached 1 million paid subscribers, and has several times more free users.