I've explained this very thing long ago in 2008My Post
Actually, here's a thought, From one console generation to the next is usually a huge technology increment.
But that's not how the CPUs and GPUs are developed, they are the result of several smaller improvements in design and technology, each step paid for by sales of those incrementally improved products.
Without the PC as a gaming platform providing a market for those products to support this ongoing development, there wouldn't be compellingly better CPUs and GPUs for the next generation of consoles so either cycles would be MUCH longer and/or the next generation consoles more expensive as they have to pay for the new hardware development, or the market would be much less lucrative and not worthwhile.
So, I conclude that Consoles NEED PCs as gaming platforms and us PC gamers needn't worry at all.