Busting a DX pileup is definitely an art form. When the DX station signs with someone else or calls QRZ, then the birds start chirping... cacophony! I found that by pausing a bit and getting my callsign in the clear (following all the chirping) I would often score. Didn't always work, but very often did. Patience, grasshopper, patience. But, I too have wasted hours trying to contact one of those rare ones. Hit or miss for sure at times.