So what? Did you have to spend $$ to buy that corruption? No. No one has to. It's nice to have the option to buy a BoE, for which any serious guild can find the gold. It's also nice to have the option of spending $$ if you are so inclined. But the fact is that it is an option that very few will ever excercise due to supply limitations. And because so few people will be making use of them, the requirement to buy them in order to be competitive is null and void, unless you're at the very top end and need every little advantage you can get to beat the next team. And even then, because you buy them with gold, not $$, there is still no need to spend $$, as was proven by Method and Limit who did spend loads of gold to buy the few available early BoEs, but didn't buy even a single token to do so.
For the most part though, these BoEs are a by-product of successful raiders, not a requirement to successfully raid.
I am not hand waving anything away. I am differentiating between the need for decent corruptions, and the need for spending $$ to get them.