I think, at least for new shooters, the additional cost of cleaning equipment over and above the cost and the gun and ammunition is probably the number one reason good guns get destroyed.
I founded TFB in 2007 and over 10 years worked tirelessly, with the help of my team, to build it up into the largest gun blog online. I retired as Editor in Chief in 2017. During my decade at TFB I was fortunate to work with the most amazing talented writers and genuinely good people!