I'm inclined to say these CPUs are all still relevant today, so they've maintained their value to some degree? They aren't "e-waste" yet. We haven't really seen massive generational gains in the CPU market for a while. With the way inflation has been, prices have probably gone up overall too...also forgive my ignorance, these cpus and boards are 7/8 years old now right? why are people still selling em for so much?
What are you building with all these chips though?