Long Junk, Short Treasuries?

Since I didn't know how to chart credit spreads, I thought that the difference in the prices of HYG (Junk Bond ETF) and TLT (Long Term Treasuries ETF) could be useful. I found that this "indicator" is at a long-term support first stablished on early 2009 (which formed a bullish divergence that started this bull market).

I don't trade bonds, so I would appreciate the input from bond traders, Is this just an anecdote? Will oil recover in time to save many businesses in the industry (and their lenders) and at the same time keep deflation away? Will support be broken and signal the end of the bull market? Is my idea just laughable?

Note: Using a ratio instead of a difference shows almost the same picture.